Car codes meaning

Car codes meaning DEFAULT

OBD Codes Explained

OBD codes can confuse pretty much everyone...even mechanics. Just because you have an auto diagnostic codes for a certain part on the car, it does not mean that that part needs to be replaced. It means that that SYSTEM is having a problem and it needs further diagnose to determine why the computer is setting the code.

This problem is made worse by auto parts stores that are trying to sell auto parts. Some of them (definitely not all) will try to get you to buy the part that they think is the problem simply by reading the auto diagnostic codes.

That being said I still advise you to go to your local auto parts store to get the codes read unless you have a great local mechanic that you know and trust. Auto parts stores will usually read them for free. The key is to not let the guy at the store talk you into buying any parts. His job is to sell you a part, not figure out what is wrong with your car.

After you know the code you can come back to this site and look up the meaning as well as common causes and diagnostic aids. On the next few pages of this section you will find an article that I've written about the most common OBD codes and the things that commonly cause the problem. Let's take a look at what OBD codes actually are.

Different Types of OBD Codes Explained

Reading OBD Codes

Most codes that you will see are "generic", usually starting with P0xxx, but there are also codes called "manufacturer codes". Information about them is harder to find because these are more specific.

If you are looking for manufacturer specific codes, I recommend you turn to a good online repair manual.

To troubleshoot, repair and maintain your vehicle, you'll need diagnostic and repair information that is specific to your car or truck. For this I personally use and recommend ALLDATAdiy. With full manuals for over 30,000 vehicles online, you will find an exact match for your vehicle's year, make and model.

Besides being cheaper than a factory manual, they also offer step by step repair instructions and detailed diagrams beyond what is found in most printed manuals. Click here for a sample of their diagnostic and repair information.

Car sensors are responsible for generating auto diagnostic codes - Click here to learn about the different types of car sensors.

Understanding Check Engine Light Codes

This information should work for any vehicle built from 1996 to today (there will be exceptions though).

Example P0340 (Camshaft sensor code)
1st Digit: B is for Body, C is for Chassis, P is for Powertrain, U is for Network
2nd Digit: 0 is for SAE aka generic, 1 is for mfg (Manufacturer Specific Codes)
3rd Digit=

* 1 Fuel and Air Metering
* 2 Fuel and Air Metering Injector Circuit
* 3 Ignition System (Including Misfires)
* 4 Auxiliary Emissions Controls
* 5 Vehicle Speed Controls And Idle Control System
* 6 Computer Output Circuit
* 7 Transmission
* 8 Transmission

4th & 5th Digit - two place fault code 0-99

Types of DTC

There are two types of obd codes (DTC) that apply to OBD II. I have them listed below with Type 1 being the more important because they can cause quick and severe damage. Type 2 being not quite as important but you still need to deal with it.

Type 1

1. Emissions related (things like EVAP codes).

2. Illuminates the MIL after one "driving cycle" that has failed.

3. Creates a trouble code freeze frame (information about other things that were going on in the engine) after one "driving cycle" that has failed.

Type 2

1. Emissions related OBD codes that aren't causing lost of pollution.

2. Will set a "pending" trouble code after one failed driving cycle.

3. Will clear a "pending" trouble code after one successful driving cycle.

4. Turns on the check engine light after two consecutive failed driving cycles. Stores a freeze frame after two consecutive failed driving cycles.

OBD Codes Categories

P0100-P0199 – Fuel and Air Metering. These will be things like the mass airflow sensor and throttle body

P0200-P0299 – Fuel and Air Metering (Injector Circuit). These codes would be for things involving the fuel injectors.

P0300-P0399 – Ignition System or Misfire. If there was a bad spark plug or faulty coil you would see one of these codes.

P0400-P0499 – Auxiliary Emissions Controls. These are the famous EVAP system codes.

P0500-P0599 – Vehicle Speed Controls and Idle Control System. The idle air control valve and VSS would fall under this category.

P0600-P0699 – Computer Output Circuit. Sometimes these types of codes point to a faulty computer.

P0700-P0999 – Transmission Codes. Many times there is a code set in the engine computer that simply lets the driver know that there is a fault in the transmission computer and the TCU needs to be scanned for codes.

Now you have a better idea of what makes up a DTC (Diagnostic Trouble Code). You can see that every digit has it's purpose. You also know which system is having the problem just by knowing what the first few numbers are. Let's take a look at some specific codes and find out what the likely fixes are.

Like and Share

Sours: https://www.myautorepairadvice.com/obd_codes.html

Got your car scanned, found an OBD2 code, and want to know what it is?

Don’t worry! All car diagnostic codes are here for you to discover.

In this article, you’ll find what any OBD2 code means, the causes, symptoms, and how to fix it. We also offer code lists in PDF for free download.

Let’s go!!

All OBD2 Codes Lookup

Search below all generic and manufacturer-specific OBD2 fault codes and their meaning in most of the popular car makes such as Acura, Audi, BMW, Chevrolet, Dodge, Chrysler, Jeep, Ford, Honda, Hyundai, Infiniti, Isuzu, Jaguar, KIA, Land Rover, Lexus, Mazda, Mitsubishi, Nissan, Subaru, Toyota, and VW, etc.


What is an OBD2 Code?

obd2 codes samples

OBD is short for onboard diagnostics. It refers to a vehicle’s electronic system that performs self-diagnosis and reporting. Whenever a problem is detected, the system records it as a unique code. That code is known as a diagnostic trouble code (DTC). As a vehicle owner or mechanic, you can pull that code and interpret it to understand the nature of the problem. For example, if the car gives you the P0201 code, it means that there’s a malfunction in cylinder 1 of the injector circuit. Your job is to pinpoint the issue and fix it.

Now, with that in mind, OBDII codes are trouble codes specific to OBD2 vehicles. These are generally cars, SUVs, light trucks, etc., made/sold in the US since 1996. In other words, if an automobile is a 1996 or newer model, it is OBD2-compliant. And that also means that it uses OBD-II codes to do self-diagnosis and reporting. I’ll be using all three interchangeably all through the post, be sure not to get confused.

Table of Contents

How to Read OBD2 Codes

OBD provides monitoring for various systems. They include the engine control module, body, chassis, etc. When you look at an OBD2 code, you can immediately tell where the fault is by reading the letters and numbers it contains. Below is a breakdown.

Explanation of OBD2 codes

The First Character (Letter)

All OBDII codes start with a letter that denotes the part of the vehicle that has a fault. Let’s check it out, shall we?

P – Powertrain. It includes the engine, transmission, and all the associated accessories.

U – Network & Vehicle Integration. These are functions that are managed and shared by onboard computer systems.

B – Body. These are parts mainly found in the passenger compartment area.

C – Chassis. It covers mechanical systems and functions like steering, suspension, and braking.

The Second Character (Number)

A number usually follows the first letter. This number can only be ‘0’, ‘1’, ‘2’, or ‘3’.

0 – If it’s a ‘0’, ‘2’, or ‘3’, the code is a standardized (SAE) code; also known as generic code

1 – If it’s a ‘1’, you’re looking at a manufacturer-specific code

The Third Character (Number/Letter)

This number denotes the particular vehicle system that has a fault. There are eight systems in total:

0 – Fuel and air metering and auxiliary emission controls

1 – Fuel and air metering

2 – Fuel and air metering (injector circuit)

3 – Ignition systems or misfires

4 – Auxiliary emission controls

5 – Vehicle speed control and idle control systems

6 – Computer and output circuit

7 – Transmission

A-F – Hybrid Trouble Codes

The Fourth And Fifth Characters (Number)

The final piece of a DTC is a two-digit number. This number defines the exact problem that you’re dealing with. It can be any number between 0 and 99.

As you can see, a typical DTC has five characters in total, and each one of those characters gives it a description. For example, if you get the code P0219, it means that the car has an engine over-speed condition.

The ‘P’ means that the problem is in the powertrain. The ‘0’ means that it’s a generic code, while the ‘2’ refers to the fuel and air metering (injector circuit) system. The last two digits (19) define the problem, i.e., an over-speed condition.

Want to know more about codes and their meanings? Below is a more comprehensive OBD codes list.As mentioned already, DTC codes that start with ‘P’ relate to the powertrain. Those that begin with ‘U’ are for the network and vehicle integration system. The letter ‘B’ refers to the vehicle’s body, while ‘C’ is for the chassis.


Bonus: Best Professional OBD2 Scanners for DIY 2021

Meaning and Fix guide of OBD2 codes

OBD2 Codes List PDF for FREE Download

Generic Powertrain OBD2 Trouble Codes List PDF

Generic Chassis, Network, and Body Codes [PDF]

Manufacturer-Specific OBD2 Codes [PDF]

To download your vehicle OBD2 code list, click the link you want:

Read more: Why Air Conditioner Only Works When My Car Is Moving?

OBD2 Codes

Below are the details of the top popular OBDII codes with meaning, causes, and fixes.

P0010 Intake Camshaft Position Actuator Circuit / Open (Bank 1)

The P0010 code happens when the ‘bank 1’ camshaft and the crankshaft have a mechanical timing variation. The problem occurs when the engine experiences high RPM. The ECM doesn’t correctly adjust valve lift at high RPM.

Main Symptoms:

  • Check Engine Light comes on
  • The engine performs poorly at high RPM
  • Car runs roughly
  • Lower fuel economy
  • Car fails the emission test

Possible Causes:

  • Sludge in engine oil
  • Faulty OVC (oil control valve)
  • Internal damage to ECM
  • ECM timing is out of sync
  • Wiring damage
  • Malfunction of crankshaft or camshaft sensor
  • A short in VCT/VVT circuit or the circuit is open

Diagnostic Steps:

  • Use an advanced diagnostic tool to pull engine codes
  • Inspect the VVT/VCT solenoid system for dirty oil
  • Inspect the circuit for wiring problems

Read more

P0011 Intake Camshaft Position Timing – Over-Advanced (Bank 1)

The P0011 code is triggered when the camshaft timing for bank 1 is above the limit set by the ECM. This situation causes an over-advanced condition that occurs either during retarding or advancing the camshaft timing.

Main Symptoms:

  • Check Engine Light comes on
  • Hard starting
  • Poor idle
  • Car may run rough or stall
  • Poor fuel economy
  • Car may fail an emission test

Possible Causes:

  • Camshaft remains advanced despite ECM commanding it to retard
  • Bank 1 oil control solenoid may be clogged or stuck
  • Oil may be too thick and is thus blocking passages in bank 1
  • Wiring problems in VCT/VVT
  • Oil continuously flows to VCT piston chambers open

Diagnostic Steps:

  • Check that engine oil is clean and has the recommended viscosity
  • Visually inspect the wiring in the CVT system
  • Pull engine codes and live data using an advanced diagnostic tool

Read more

P0012 Intake Camshaft Position Timing – Over-Retarded (Bank 1)

The P0012 code is triggered when bank 1 has an over-retarded timing condition that occurs either during retarding or advancing.

Main Symptoms:

  • Check Engine Light comes on
  • Hard starting
  • Poor fuel economy
  • Car may run rough or stall
  • Car may fail an emission test

Possible Causes:

  • Camshaft timing is incorrect
  • Wiring problems in VCT/VVT
  • Oil continuously flows to the VCT piston chamber
  • Timing valve solenoid control has failed and is stuck in the open position
  • Oil may be too thick and is thus blocking passages in bank 1

Diagnostic Steps:

  • Check that engine oil is clean
  • Visually inspect the wiring in the CVT system
  • Pull engine codes and live data using an advanced diagnostic tool
  • Using the bidirectional scanner, command the timing valve solenoid control valve to open and close, then see if camshaft timings change. If they change, it means the valve is not the problem

Read more

P0014 Exhaust Camshaft Position Timing – Over-Advanced (Bank 1)

The P0014 code happens when bank 1 camshaft has an over-advanced timing condition that occurs either during retarding or advancing.

Main Symptoms:

  • Check Engine Light comes on
  • Hard starting
  • Poor fuel economy
  • Car may run rough or stall
  • Car may fail emission test

Possible Causes:

  • Camshaft timing is incorrect
  • Wiring problems in VCT/VVT
  • Oil continuously flows to the VCT piston chamber
  • Timing valve solenoid control has failed and is stuck in the open position
  • Oil may be too thick and is thus blocking passages in bank 1

Diagnostic Steps:

  • Check that engine oil is clean and full in the tank
  • Visually inspect the wiring in the CVT system
  • Pull engine codes and live data using the advanced diagnostic tool

Using the bidirectional scanner, command the timing valve solenoid control valve to open and close, then see if camshaft timings change. If they change, it means the valve is not the problem

Read more

P0016 Crankshaft Position Camshaft Position Correlation Bank 1 Sensor A

The P0016 code occurs when the crankshaft and camshaft signals are out of time. Meaning the ECM can detect that the crankshaft’s timing and that of the camshaft do not correlate.

Main Symptoms:

  • Check Engine Light comes on
  • The engine may crank but fail to start
  • The engine may continue to run but will record poor performance
  • Rattling sound in the harmonic balancer
  • Poor fuel economy

Possible Causes:

  • The timing chain is overstretched
  • Tone ring on the camshaft and/or crankshaft is has slipped or broken
  • Timing chain has jumped teeth and put camshaft timing out of position
  • Problems with camshaft phaser and putting the phaser out of position
  • Wiring to crank/cam sensor is damaged

Diagnostic Steps:

  • Inspect oil control valve (OCV) for connection or wiring problems
  • Check that engine oil is clean, full, and has the correct viscosity
  • Pull engine codes and live data using an advanced diagnostic tool
  • Using the bidirectional scanner, command the OVC on and off, then see if camshaft timings change. If they change, it means the valve is not the problem

Read more

P0037 Heated Oxygen Sensor (H02S) Heater Control Circuit Bank 1 Sensor 2

The P0037 code is triggered when bank 1, sensor 2 of the O2 sensor heater circuit is faulty. For example, the engine isn’t achieving a closed-loop and causes the car to increase emissions.

Main Symptoms:

  • Check Engine Light comes on
  • Longer time needed to achieve a closed-loop
  • Decreased fuel economy
  • The engine may go into the fixed fuel mix

Possible Causes:

  • H02S sensor in bank 1, circuit 2 is not sending the correct signal to ECM
  • Damaged or failed element in the heater circuit
  • Open in O2 sensor heater’s circuit
  • Open/short in O2 sensor heater’s battery
  • Defective ECM (this is the least likely cause)

Diagnostic Steps:

  • Inspect wiring and power to the O2 sensor and ensure there’s no damage/open/short
  • Use code reader to pull engine codes
  • Check the voltage of the O2 sensor and ensure it matches the manufacturer’s specs
  • Replace O2 sensor if necessary

Read more

P0102 Mass or Volume Air Flow Circuit low Input

The P0102 code happens when the mass airflow (MAF) sensor does not perform within the standard expectation and sends a lower signal than usual (due to low voltage).

Main Symptoms:

  • Check Engine Light comes on
  • Extremely low fuel consumption and thus internal engine problems
  • Engine runs roughly
  • Car idles and stalls frequently

Possible Causes:

  • Defective MAF sensor
  • Presence of dirt and debris in MAF (restricts airflow)
  • Leaks in the air intake system
  • Improper wiring of the circuit to MAF sensor

Diagnostic Steps:

  • Use code reader to pull engine codes
  • Visually inspect MAF sensor wiring and circuit
  • Check for air leaks in the air intake system
  • Inspect MAF to see if there are dirt and debris

Read more

P0106 Manifold Absolute Pressure/Barometric Pressure Circuit Range/Performance Problem

The P0106 code is triggered when the Powertrain Control Module (PCM) has not detected a change in engine speed, throttle angle, and exhaust gas recirculation (EGR) despite an increase in manifold absolute pressure (MAP). An increase in MAP indicates an increase in engine load.

Main Symptoms:

  • Check Engine Light comes on
  • Poor fuel economy
  • Engine fails to idle
  • The engine produces black smoke (visible at tailpipe)
  • Erratic acceleration

Possible Causes:

  • Faulty MAP sensor
  • The air intake component is loose, cracked, or doesn’t have its plastic fitting
  • Water or dirt affecting connector to MAP sensor
  • Corrosion may be causing the poor signal to and from the MAP sensor
  • PCM is defective (least likely but not unlikely)

Diagnostic Steps:

  • Use an advanced scanner to pull engine codes.
  • With that scanner, diagnose the MAP sensor when the engine is off and the key is on. It should be similar or close to barometric pressure (BARO) reading.
  • Start the engine and see if MAP sensor readings drop significantly. If they do, the sensor is working correctly.

Read more

P0113 Intake Air Temperature Circuit High Input (Sensor 1)

P0113 means that the signal voltage from the intake air temperature (IAT) is above 5V, which is more than the expected range.

Main Symptoms:

  • Check Engine Light comes on
  • The engine may run extra lean

Possible Causes:

  • Defective IAT sensor
  • Loose or faulty wiring at IAT sensor
  • Open or short in IAT ground circuit, signal circuit, or reference circuit
  • PCM is defective (least likely but not unlikely)

Diagnostic Steps:

  • Use an advanced scanner to pull engine codes.
  • View live data from the IAT sensor. If the result is less than -30 degrees Celsius, then the sensor is likely to be faulty. Otherwise, it’s probably an intermittent problem.
  • Check the wiring for opens and loose connections.

Read more

P0118 Engine Coolant Temperature Circuit High Input

P0118 means that the PCM has determined that ECT is less than freezing temp, yet the engine has been running for several minutes, which shouldn’t happen.

Main Symptoms:

  • Check Engine Light comes on
  • Poor fuel economy
  • The engine fails to idle and may not start completely
  • The engine produces black smoke (visible at tailpipe)

Possible Causes:

  • Defective ECT sensor
  • Open or short in ECT signal or ground circuit
  • PCM is defective (least likely but not unlikely)

Diagnostic Steps:

  • Using an OBD2 scanner, check the ECT. If it’s a logical reading, the problem is intermittent.
  • Perform a wiggle test while looking out for drop-outs. If there are any, there’s a bad connection to or from the ECT sensor.

Read more

P0121 Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance Problem

P0121 happens when the PCM has detected that the throttle position sensor (TPS) voltage is more or less than it should be for the current RPM.

Main Symptoms:

  • Check Engine Light comes on
  • The car produces black smoke (visible at tailpipe)
  • Car stumbles when you accelerate or decelerate
  • The engine may fail to start completely

Possible Causes:

  • Defective TPS
  • Open or short in TPS circuit
  • Loose or bad connection to TPS
  • PCM is defective (least likely but not unlikely)

Diagnostic Steps:

  • Visually inspect all wiring to TPS for loose, open, or short connections

Using an OBD2 scanner, check for live data and freeze-frame data from TPS. If it doesn’t read 0.5 at idle and 4.5 at full throttle, the TPS is faulty

Read more

P0122 Throttle/Pedal Position Sensor/Switch A Circuit Low Input

P0122 means that the PCM reports that the TPS has recorded a lower voltage than the minimum limit. The value varies from one car to another, but the code may come when the voltage hits 0.20V or less.

Main Symptoms:

  • Check Engine Light comes on
  • Extremely high idle
  • Rough or low idle
  • Car stalls
  • Acceleration is low or completely lacking

Possible Causes:

  • Defective TPS
  • Open or short in TPS circuit
  • Improper mounting of TPS after replacement
  • TPS has loosened
  • PCM is defective (least likely but not unlikely)

Diagnostic Steps:

  • Visually inspect all wiring to TPS for loose, open, or poor connections.
  • Check that TPS is tightly in position, especially if you recently replaced it.

Read more

P0128 Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)

P0128 OBD2 code means the PCM has detected that the engine has not attained the required temperature despite it is on for enough time to reach that temperature.

Main Symptoms:

  • Check Engine Light MAY come on
  • Engine temp drops when the vehicle is in high speed
  • Engine takes abnormally long to warm

Possible Causes:

  • Most likely cause is that thermostat is leaking or stuck in open position
  • Engine coolant level is too low
  • Defective IAT sensor
  • Defective ECT sensor
  • Defective cooling fan

Diagnostic Steps:

  • Check whether coolant strength and level are in the recommended range
  • Check whether IAT sensor, ECT sensor and coolant fan are working
  • If all the above are okay then the thermostat is the problem

Read more

P0131 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1)

P0131 triggers when the ECM has determined a low voltage condition in bank 1 sensor 1; i.e., O2 sensor voltage remained too low for longer than 2 minutes.

Main Symptoms:

  • Check Engine Light comes on
  • The car produces black smoke (visible at tailpipe)
  • Poor fuel economy
  • The engine may fail to start completely
  • If it starts, it may run rough and/or stumble

Possible Causes:

  • Mostly a problem related to corrosion, loose terminal, or burnt wire in the O2 sensor 1 connector
  • Defective O2 sensor
  • Open or short in the wiring to the O2 sensor
  • O2 circuit is experiencing high resistance

Diagnostic Steps:

  • Visually inspect all wiring to O2 sensor 1 for loose, open, or short connections
  • Use a wiggle test to determine where the voltage drops out
  • Using an OBD2 scanner, check whether sensor 1 of bank 1 is switching properly

Read more

P0133 O2 Sensor Circuit Slow Response (Bank 1 Sensor 1)

P0133 occurs when the O2 sensor or ECM can’t adjust the air to fuel ratio as it’s supposed to even when the engine is running.

Main Symptoms:

  • Generally doesn’t come with symptoms. However, in some cases, the Check Engine Light may come on, and fuel economy may reduce

Possible Causes:

  • The first O2 sensor in bank 1 is faulty
  • Short, open, or broken wire in the O2 sensor circuit
  • Exhaust leak

Diagnostic Steps:

  • Visually inspect all wiring to the first O2 sensor for loose, open, or short connections
  • • Use a wiggle test to determine where the voltage drops out
  • • Visually check for exhaust leaks or air inlet leaks
  • • Using an OBD2 scanner, check whether sensor 1 of bank 1 is switching properly

Read more

P0135 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)

Usually, when the O2 heater attains operating temperature, the O2 sensor switches based on ambient temp. If ECM determines that the O2 sensor took too long to switch, this code is set. It applies to the first sensor of bank 1

Main Symptoms:

  • Check Engine Light comes on
  • Poor fuel economy

Possible Causes:

  • Short, open, or broken wire in O2 heating system
  • High resistance in O2 heater element or circuit

Diagnostic Steps:

  • Visually inspect all wiring to the first O2 sensor (bank 1) for loose, open, or short connections
  • Use a wiggle test to determine where the voltage drops out
  • If the code is persistent, replace the O2 sensor

Read more

P0136 O2 Sensor Circuit Malfunction (Bank 1 Sensor 2)

P0136 means that the ECM has determined a low voltage condition in bank 1 sensor 2; i.e., O2 sensor voltage remained too low for longer than 2 minutes.

Main Symptoms:

  • Check Engine Light comes on
  • The car produces black smoke (visible at tailpipe)
  • Poor fuel economy
  • The engine may fail to start completely
  • If it starts, it may run rough and/or stumble

Possible Causes:

  • Mostly a problem related to corrosion, loose terminal, or burnt wire in the O2 sensor 2 connector
  • Defective O2 sensor
  • Open or short in the wiring to the O2 sensor
  • O2 circuit is experiencing high resistance

Diagnostic Steps:

  • Visually inspect all wiring to O2 sensor 2 for loose, open, or short connections
  • Use a wiggle test to determine where the voltage drops out
  • Using an OBD2 scanner, check whether sensor 2 of bank 1 is switching properly

Read more

P0137 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 2)

Basically the same as P0136. The P0137 is triggered when the PCM has detected that the O2 sensor may be inactive.

Main Symptoms:

  • Generally doesn’t come with symptoms. However, in some cases, the Check Engine Light may come on, and fuel economy may reduce

Possible Causes:

  • Faulty O2 sensor
  • Short, open, or broken wire in the O2 sensor circuit
  • Defective heater circuit in the O2 sensor
  • High resistance in O2 heater element or circuit
  • Faulty fuel pump regulator resulting in very high or very low fuel pressure
  • Exhaust leak

Diagnostic Steps:

  • Visually inspect all wiring to O2 sensor for loose, open, or short connections
  • Use a wiggle test to determine where the voltage drops out
  • Visually check for exhaust leaks or air inlet leaks
  • If the code is persistent, replace the O2 sensor

Read more

P0138 O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)

The P0138 code means the heated O2 sensor in bank 1 sensor 2 gives a higher voltage reading than it should. For most vehicles, the code comes when voltage exceeds 1.5V.

Main Symptoms:

  • Generally doesn’t come with symptoms. However, in some cases, the Check Engine Light may come on, and fuel economy may reduce

Possible Causes:

  • Fuel temp is excessively high
  • Short, open, or broken wire in the O2 sensor circuit

Diagnostic Steps:

  • Visually inspect all wiring to O2 sensor for loose, open, or short connections
  • Use a wiggle test to determine where the voltage drops out
  • Using an OBD2 scanner, check whether sensor 1 of bank 2 is switching properly

Read more

P0141 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)

P0141 means when the O2 heater attains operating temperature, the O2 sensor switches based on ambient temp. If ECM determines that the O2 sensor took too long to switch, this code is set. It applies to the second sensor of bank 1.

Main Symptoms:

  • Check Engine Light comes on
  • Poor fuel economy

Possible Causes:

  • Short, open, or broken wire in O2 heating system
  • High resistance in O2 heater element or circuit

Diagnostic Steps:

  • Visually inspect all wiring to the second O2 sensor (bank 1) for loose, open, or short connections
  • Use a wiggle test to determine where the voltage drops out
  • If the code is persistent, replace the O2 sensor

Read more

P0161 O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 2)

P0161 triggers when the O2 heater attains operating temperature, O2 sensor switches based on ambient temp. If ECM determines that the O2 sensor took too long to switch, this code is set. It applies to the second sensor of bank 2.

Main Symptoms:

  • Check Engine Light comes on
  • Poor fuel economy

Possible Causes:

  • Short, open, or broken wire in O2 heating system
  • High resistance in O2 heater element or circuit

Diagnostic Steps:

  • Visually inspect all wiring to the second O2 sensor (bank 2) for loose, open, or short connections
  • Use a wiggle test to determine where the voltage drops out
  • If the code is persistent, replace the O2 sensor

Read more

P0171 System Too Lean (Bank 1)

P0171 indicates that there is a lean condition in bank 1; i.e., there’s excess oxygen in the exhaust

Main Symptoms:

  • Significant decrease in engine power
  • Car hesitates then surges upon acceleration
  • Rough idle

Possible Causes:

  • Dirty or defective MAF sensor
  • MAF sensor has a vacuum leak
  • Positive Crankcase Ventilation (PCV) valve is stuck in the open position
  • Leak either in PCV or vacuum system

Diagnostic Steps:

  • Inspect MAF sensor in bank 1 for dirt and debris
  • Check whether fuel pressure is correct
  • Check vacuum and PCV for leaks
  • Run a smog test using an OBD2 scanner

Read more

P0172 System Too Rich (Bank 1)

P0172 happens when there’s a rich condition in bank 1; i.e., there’s too little oxygen in the exhaust condition in bank 1; i.e., there’s excess oxygen in the exhaust.

Main Symptoms:

  • Generally doesn’t come with symptoms, but the Check Engine Light may come on, and the engine may misfire

Possible Causes:

  • Dirty or defective MAF sensor
  • MAF sensor has a vacuum leak
  • The problem relating to fuel pressure or delivery

Diagnostic Steps:

  • Inspect MAF sensor in bank 1 for dirt and debris
  • Check whether fuel pressure is correct
  • Inspect fuel lines and injectors for any leaks/openings and dirt
  • Check vacuum, PCV, and exhaust for leaks
  • Run a smog test using an OBD2 scanner

Read more

P0174 System Too Lean (Bank 2)

This code means that there’s a lean condition in bank 2; i.e., there’s excess oxygen in the exhaust

Main Symptoms:

  • Significant decrease in engine power
  • Car hesitates then surges upon acceleration
  • Rough idle

Possible Causes:

  • Dirty or defective MAF sensor
  • MAF sensor has a vacuum leak
  • Positive Crankcase Ventilation (PCV) valve is stuck in the open position
  • Leak either in PCV or vacuum system

Diagnostic Steps:

  • Inspect MAF sensor in bank 2 for dirt and debris
  • Check whether fuel pressure is correct
  • Check vacuum and PCV for leaks
  • Run a smog test using an OBD2 scanner

Read more

P0300 Random/Multiple Cylinder Misfire Detected

When the code P0300 is triggered, it means that PCM has detected that there’s an engine cylinder that’s not firing properly. It could be one or more cylinders. PCM hasn’t specified the exact cylinder

Main Symptoms:

  • Check Engine Light comes on
  • Check Engine Light may flash
  • Engine lacks power
  • The engine may be hard to start
  • The engine may stumble and hesitate frequently

Possible Causes:

  • Defective or worn out spark plugs
  • Low fuel pressure
  • Vacuum leak
  • Defective catalytic converter
  • Defective fuel injector
  • Defective coil
  • Bad camshaft position sensor
  • Defective crankshaft sensor
  • Problem with distributor

Diagnostic Steps:

  • Using a scan tool, pull codes and see if there are any other besides P0300. Address the others first
  • Inspect whether there are loose, open, or short wires in ignition coils
  • Inspect whether spark plugs and their wires are in good condition
  • Check that fuel pressure is within the recommended range
  • Inspect fuel injectors to see whether they are in good condition

Read more

P0301 Cylinder 1 Misfire Detected

The meaning of P0301 is that the PCM has detected that cylinder #1 is not firing properly.

Main Symptoms:

  • Check Engine Light comes on
  • Check Engine Light may flash
  • Engine lacks power
  • The engine may be hard to start
  • The engine may stumble and hesitate frequently

Possible Causes:

  • Defective or worn out spark plugs in cylinder 1
  • Low fuel pressure
  • Vacuum leak
  • Defective catalytic converter
  • Defective fuel injector
  • Defective coil
  • Defective camshaft position sensor
  • Defective crankshaft sensor
  • Problem with distributor

Diagnostic Steps:

  • Using a scan tool, pull codes and see if there are any other besides P0301. Address the others first
  • Inspect whether there are loose, open, or short wires in ignition coils in cylinder 1
  • Inspect whether cylinder 1 spark plugs and their wires are in good condition
  • Check that fuel pressure is within the recommended range
  • Inspect fuel injectors to see whether they are in good condition

Read more

P0302 Cylinder 2 Misfire Detected

P0302 indicates that the PCM has detected that cylinder #2 is not firing properly

Main Symptoms:

  • Check Engine Light comes on
  • Check Engine Light may flash
  • Engine lacks power
  • The engine may be hard to start
  • The engine may stumble and hesitate frequently

Possible Causes:

  • Defective or worn out spark plugs in cylinder 2
  • Low fuel pressure
  • Vacuum leak
  • Defective catalytic converter
  • Defective fuel injector
  • Defective coil
  • Defective camshaft position sensor
  • Defective crankshaft sensor
  • Problem with distributor

Diagnostic Steps:

  • Using a scan tool, pull codes and see if there are any other besides P0302. Address the others first
  • Inspect whether there are loose, open, or short wires in ignition coils in cylinder 2
  • Inspect whether cylinder 2 spark plugs and their wires are in good condition
  • Check that fuel pressure is within the recommended range
  • Inspect fuel injectors to see whether they are in good condition

Read more

P0303 Cylinder 3 Misfire Detected

The P0303 code occurs when the PCM has detected that cylinder #3 is not firing properly.

Main Symptoms:

  • Check Engine Light comes on
  • Check Engine Light may flash
  • Engine lacks power
  • The engine may be hard to start
  • The engine may stumble and hesitate frequently

Possible Causes:

  • Defective or worn out spark plugs in cylinder 3
  • Low fuel pressure
  • Vacuum leak
  • Defective catalytic converter
  • Defective fuel injector
  • Defective coil
  • Defective camshaft position sensor
  • Defective crankshaft sensor
  • Problem with distributor

Diagnostic Steps:

  • Using a scan tool, pull codes and see if there are any other besides P0303. Address the others first
  • Inspect whether there are loose, open, or short wires in ignition coils in cylinder 3
  • Inspect whether cylinder 3 spark plugs and their wires are in good condition
  • Check that fuel pressure is within the recommended range
  • Inspect fuel injectors to see whether they are in good condition

Read more

P0304 Cylinder 4 Misfire Detected

The P0304 code is triggered when the PCM has detected that cylinder #4 is not firing properly.

Main Symptoms:

  • Check Engine Light comes on
  • Check Engine Light may flash
  • Engine lacks power
  • The engine may be hard to start
  • The engine may stumble and hesitate frequently

Possible Causes:

  • Defective or worn out spark plugs in cylinder 4
  • Low fuel pressure
  • Vacuum leak
  • Defective catalytic converter
  • Defective fuel injector
  • Defective coil
  • Defective camshaft position sensor
  • Defective crankshaft sensor
  • Problem with distributor

Diagnostic Steps:

  • Using a scan tool, pull codes and see if there are any other besides P0304. Address the others first
  • Inspect whether there are loose, open, or short wires in ignition coils in cylinder 4
  • Inspect whether cylinder 4 spark plugs and their wires are in good condition
  • Check that fuel pressure is within the recommended range
  • Inspect fuel injectors to see whether they are in good condition

Read more

P0305 Cylinder 5 Misfire Detected

The P0305 code indicates that the PCM has detected that cylinder #5 is not firing properly.

Main Symptoms:

  • Check Engine Light comes on
  • Check Engine Light may flash
  • Engine lacks power
  • The engine may be hard to start
  • The engine may stumble and hesitate frequently

Possible Causes:

  • Defective or worn out spark plugs in cylinder 5
  • Low fuel pressure
  • Vacuum leak
  • Defective catalytic converter
  • Defective fuel injector
  • Defective coil
  • Defective camshaft position sensor
  • Defective crankshaft sensor
  • Problem with distributor

Diagnostic Steps:

  • Using a scan tool, pull codes and see if there are any other besides P0305. Address the others first
  • Inspect whether there are loose, open, or short wires in ignition coils in cylinder 5
  • Inspect whether cylinder 5 spark plugs and their wires are in good condition
  • Check that fuel pressure is within the recommended range
  • Inspect fuel injectors to see whether they are in good condition

Read more

P0306 Cylinder 6 Misfire Detected

The P0306 code is triggered when the PCM has detected that cylinder #6 is not firing properly.

Main Symptoms:

  • Check Engine Light comes on
  • Check Engine Light may flash
  • Engine lacks power
  • The engine may be hard to start
  • The engine may stumble and hesitate frequently

Possible Causes:

  • Defective or worn out spark plugs in cylinder 6
  • Low fuel pressure
  • Vacuum leak
  • Defective catalytic converter
  • Defective fuel injector
  • Defective coil
  • Defective camshaft position sensor
  • Defective crankshaft sensor
  • Problem with distributor

Diagnostic Steps:

  • Using a scan tool, pull codes and see if there are any other besides P0306. Address the others first
  • Inspect whether there are loose, open, or short wires in ignition coils in cylinder 6
  • Inspect whether cylinder 6 spark plugs and their wires are in good condition
  • Check that fuel pressure is within the recommended range
  • Inspect fuel injectors to see whether they are in good condition

Read more

P0316 Misfire Detected On Startup (First 1000 Revolutions)

The P0316 code occurs when the PCM has detected a misfire of less than 1,000 revolutions after startup.

Main Symptoms:

  • Check Engine Light comes on
  • Engine lacks power
  • Rough idle

Possible Causes:

  • Defective or worn out spark plugs
  • No fuel
  • Low fuel pressure
  • Vacuum leak
  • Defective catalytic converter
  • Defective fuel injector
  • Defective coil
  • Defective crankshaft sensor
  • Wiring fault in the crankshaft position sensor
  • Problem with PCM

Diagnostic Steps:

  • Pull all codes, then address other misfire codes first
  • Check all wiring and connectors in crankshaft and camshaft position sensors
  • Review freeze frame data to narrow down the problem further

Read more

P0325 Knock Sensor 1 Circuit Malfunction (Bank 1 or Single Sensor)

The P0325 code is triggered when the PCM has detected that the engine’s knock sensor 1 in-circuit bank 1 is not working properly.

Main Symptoms:

  • Generally doesn’t come with symptoms, but Check Engine Light may come on.
  • The engine may also lose power

Possible Causes:

  • The first sensor in circuit bank 1 may be faulty
  • Open or short in the wiring to the sensor
  • Problem with engine coolant
  • The engine is excessively lean
  • PCM has failed (least likely)

Diagnostic Steps:

  • Visually inspect all wiring to knock sensor 1 in circuit bank 1. Ensure there are no shorts or open wires
  • View coolant temp data to check for issues
  • If there are none, clear the code and test drive the car. If it comes back, the sensor is defective

Read more

P0335 Crankshaft Position Sensor A Circuit Malfunction

The P0335 code happens when the PCM has detected that the crankshaft position (CKP) sensor does not produce pulses or the pulses are not normal. It uses these pulses to determine the position of the crankshaft.

Main Symptoms:

  • Check Engine Light comes on
  • The engine may fail to start
  • The vehicle may run rough

Possible Causes:

  • Defective CKP sensor
  • Open or short in CKP sensor wiring
  • The timing belt is broken
  • PCM has failed (least likely)

Diagnostic Steps:

  • Start by checking if there’s an RPM signal (using a scanner)
  • If it’s not there, check all the wires and connectors to the sensor. Repair as necessary
  • Check the sensor’s resistance and compare it with the manufacturer’s recommendation. If they don’t match, replace the sensor

Read more

P0340 Camshaft Position Sensor Circuit Malfunction

This OBD2 code means that there’s a problem with the camshaft position sensor (CPS) circuit. As such, PCM can’t perform ignition spark and fuel injector timing properly.

Main Symptoms:

  • Check Engine Light comes on
  • The engine may fail to start
  • The vehicle may run rough
  • Rough idle
  • Misfire

Possible Causes:

  • Defective CPS
  • Open or short in CPS wiring
  • Defective CKP sensor
  • PCM has failed (least likely)

Diagnostic Steps:

  • Inspect wiring to CPS and ensure there are no open or broken wires
  • Check CPS voltage if it’s within the manufacturer’s specs. If it is not, replace the sensor
  • Check CKP sensor as well to determine whether it’s the source of the problem

Read more

P0401 Exhaust Gas Recirculation Flow Insufficient Detected

This code indicates that the PCM has detected an insufficient amount of EGR.

Main Symptoms: The most notable symptom is engine pinging when the vehicle is at high speed or under load

Possible Causes:

  • Defective differential pressure feedback EGR (DPFE) sensor
  • Defective EGR valve
  • EGR valve can’t open because of lack of vacuum
  • Blockage in EGR tube

Diagnostic Steps:

  • Check the EGR valve and its tubing for deposits
  • Check DPFE sensor voltage to ensure its within a specified range
  • If not, replace the sensor. If it is, replace the EGR valve

Read more

P0420 Catalyst System Efficiency Below Threshold (Bank 1)

P0420 means the Catalytic converter is not working as efficiently as it should, and the vehicle is therefore emitting more harmful substances.

Main symptoms:

  • Check Engine Light comes on
  • Engine lacks power
  • Reduced fuel economy

Possible Causes:

  • Defective O2 sensor
  • Defective engine coolant temp
  • Wiring to downstream O2 sensor is damaged or improperly done
  • Leaking fuel injector
  • Oil is contaminated
  • Using leaded fuel where unleaded fuel was required
  • Defective catalytic converter, exhaust pipe, muffler, or exhaust manifold

Diagnostic Steps:

  • Inspect exhaust system for damage and leaks.
  • Check the voltage of the downstream O2 sensor while the engine is running. If it’s not steady (jumpy between .1 and .9 V), the catalytic converter needs replacing.

Read more

Bonus:How to Test an O2 Sensor with a Scan Tool

P0440 Evaporative Emission Control System Malfunction

The code P0440 means a component in the EVAP system is not working properly

Main Symptoms: Check Engine Light may come on

Possible Causes:

  • The gas cap is not working or has not been installed properly
  • The canister is plugged and defective
  • Purge solenoid has failed

Diagnostic Steps:

  • Inspect gas cap to see if it’s installed tightly
  • Check for disconnected or cracked EVAP hoses
  • Inspect the charcoal canister and fuel tank for leaks and damages
  • Check that the purge valve (solenoid) has no leaks

Read more

P0441 Evaporative Emission Control System Incorrect Purge flow

P0441 code is triggered when the PCM finds that there’s no purge flow (i.e., purge control valve is still closed) despite commanding a purge

Main Symptoms:

  • Check Engine Light may come on
  • Rough or erratic idle

4. Possible Causes:

  • Loose or damaged EVAP hoses
  • Defective purge valve
  • The gas cap is loose, missing, or damaged
  • The charcoal canister is damaged or defective

5. Diagnostic Steps:

  • Inspect gas cap to see if it’s installed tightly
  • Check for disconnected or cracked EVAP hoses
  • Inspect the charcoal canister and fuel tank for leaks and damages
  • Check that the purge valve (solenoid) has no leaks

Read more

P0442 Evaporative Emission Control System Leak Detected (small leak)

The code P0442 indicates that the PCM has detected a very small vapor leak somewhere in the EVAP control system

Main Symptoms:

  • Check Engine Light may come on
  • Reduced fuel economy

Possible Causes:

  • Loose or damaged EVAP hoses
  • Defective purge valve
  • The gas cap is loose, missing, or damaged
  • The charcoal canister is leaking
  • The fuel tank is leaking

Diagnostic Steps:

  • Inspect gas cap to see if it’s installed tightly
  • Check for disconnected or cracked EVAP hoses
  • Inspect the charcoal canister and fuel tank for leaks and damages
  • Check that the purge valve (solenoid) has no leaks
  • If the above doesn’t narrow down the problem, perform a smoke test

Read more

P0443 Evaporative Emission Control System Purge Control Valve circuit Malfunction

This code means that either there’s an open in the purge control valve circuit or the circuit has an abnormal voltage (too high or too low)

Main Symptoms:

  • Check Engine Light may come on
  • Car may have a lean condition

Possible Causes:

  • Purge solenoid has short or open
  • Short or open somewhere in the wiring harness to purge valve
  • Driver circuit in PCM has an open or short
  • Water intrusion has caused the connector to break or wear out

Diagnostic Steps:

  • Using a scan tool, command purge valve to open. Listen for a clicking sound (one or many times)
  • If it doesn’t click, examine solenoid and connectors for breakages and signs of extreme wearing out
  • Check all the circuits for wiring problems

Read more

P0446 Evaporative Emission Control System Vent Control Circuit Malfunction

The P0446 indicates that the PCM has detected an open or short in the EVAP control circuit or a short to ground circuit

Main Symptoms: 

  • Check Engine Light comes on

Possible Causes:

  • Defective EVAP vent valve
  • Blockage in vent valve
  • The vent valve control circuit has an open or short

Diagnostic Steps:

  • Examine all wiring to vent valve
  • If the above checks out, replace the vent valve

Read more

P0449 Evaporative Emission Control System Vent Valve/Solenoid Circuit Malfunction

This code happens when the PCM has detected a problem in the circuit that controls the EVAP system vent.

Main Symptoms: 

  • Check Engine Light comes on

Possible Causes:

  • Defective EVAP vent valve
  • Wiring issue in the EVAP vent valve
  • Circuit issue in the EVAP vent valve

Diagnostic Steps:

  • Check all wires leading to the vent valve for shorts and opens
  • Check fuses that power the vent solenoid (in case there are any)
  • Examine if the vent valve has cracks or openings
  • Using a bidirectional scanner, actuate the valve to see if it’s working

Read more

P0452 Evaporative Emission System Pressure Sensor/Switch Low

The P0452 code indicates that the PCM has detected that the fuel tank pressure is abnormally low.

Main Symptoms: 

  • Check Engine Light comes on

Possible Causes:

  • Defective fuel tank pressure (FTP) sensor
  • Wiring problem in the circuits that lead to FTP sensor
  • Broken or cracked vapor line (either to the tank or vacuum canister)
  • Loose gas cap leading to loss of vacuum
  • Leaking gasket in the fuel pump module

Diagnostic Steps:

  • Check vapor hoses for any breakages and opens
  • Since diagnosing this problem is extremely hard (due to the location of the FTP sensor), it’s recommended that you get a professional to do the job

Read more

P0455 Evaporative Emission Control System Leak Detected (large leak)

P0455 code means that PCM has detected a large vapor leak somewhere in the EVAP control system

Main Symptoms:

  • Check Engine Light may come on
  • Reduced fuel economy

Possible Causes:

  • Loose or damaged EVAP hoses
  • The gas cap is loose, missing, or damaged
  • Non-compatible gas cap

Diagnostic Steps:

  • Inspect gas cap to see if it’s installed tightly
  • Check for disconnected or cracked EVAP hoses
  • Inspect the charcoal canister and fuel tank for leaks and damages
  • If the above doesn’t work, replace the gas cap

Read more

P0456 Evaporative Emissions System – Small leak detected

P0456 code means the FTP sensor has detected a small leak in the EVAP system.

Main Symptoms: Check Engine Light comes on

Possible Causes:

  • Faulty gas cap
  • A leak in fuel tank hoses or EVAP hoses
  • A leak in the vent valve or purge valve
  • A leak in the EVAP canister

Diagnostic Steps:

  • Use a bidirectional tool to activate the vent solenoid as you monitor the FTP sensor. It will tell you if the system is sealing properly or not
  • If it is, use a smoke test to determine the leak

Read more

P0457 Evaporative Emission Control System (EVAP) Leak Detected

When there’s a vacuum leak, and the EVAP system can’t draw fuel vapors into the system for efficient burning, the P0457 is triggered.

Main Symptoms:

  • Check Engine Light comes on
  • The smell of fuel in the exhaust
  • Reduced fuel economy

Possible Causes:

  • Check Engine Light comes on
  • The smell of fuel in the exhaust
  • Reduced fuel economy

Diagnostic Steps:

  • Inspect gas cap and check if its loose or has debris that’s preventing it from fitting tightly
  • Inspect vacuum hoses for cracks and breaks
  • Inspect charcoal canister for leaks

Read more

P0463 Evaporative Emission Control System Pressure Sensor High Input

When the fuel level sensor signal is above 5 volts for a prolonged time, P0463 happens.

Main Symptoms:

  • Check Engine Light comes on
  • Fuel light may come on and sound alarm
  • Fluctuating fuel level gauge
  • Fuel level gauge may erroneously read empty or full

Possible Causes:

  • Defective fuel level sensor
  • Problem with fuel level sensor circuit
  • Defective instrument cluster
  • Damaged fuel tank

Diagnostic Steps:

  • Visually inspect fuel tank for damage or leaks
  • Inspect wiring harness
  • Do voltage test on fuel level sensor circuit
  • If all those checkouts, you may have to replace the fuel tank

Read more

P0507 Idle Control System RPM higher Than Expected

The PCM has detected that the engine idle speed is higher than the pre-programmed RPM (typically over 200 RPM)

Main Symptoms:

  • Check Engine Light comes on

Possible Causes:

  • Vacuum leak
  • The defective positive crankcase ventilation valve
  • Leaking air intake
  • Problem with throttle body
  • Defective EVAP system
  • Defective idle air controller (IAC) or a problem with the IAC circuit
  • Failed PCM

Diagnostic Steps:

  • Check for vacuum leaks, damages, and restriction
  • Note that this code is informational more than anything, so look out for other codes that it comes with and address those first

Read more

P0700 Transmission Control System Malfunction

If the transmission control module (TCM) detects a fault in the transmission system and sets a code, the code will be triggered.

Main Symptoms:

  • Check Engine Light comes on
  • Transmission may exhibit problems

Possible Causes: Any transmission-related problem can trigger this code

Diagnostic Steps: This is only an informational code, so pull all transmission codes, address them and do a test drive to fix this code

Read More

Conclusion

“Okay, are you satisfied with this list? Any questions for me?”

Tell me more about the code you have and some problems you are facing in the comment box! I’m willing to reply to you.

Sours: https://www.obdadvisor.com/most-popular-obd2-codes/
  1. World gym shirt
  2. Ups delivery tracking
  3. San jacinto college
  4. Kiss gel fantasy

A Guide to Understanding DTC Codes

What is a DTC Code? 

A DTC, short for Diagnostic Trouble Code, is a code used to diagnose malfunctions in a vehicle or heavy equipment. While the malfunction indicator lamp (MIL)—also known as the check engine light—simply alerts drivers that there is an issue, a DTC identifies what and where the issue is. DTCs are also called engine vehicle fault codes codes, and can be read with a scanner that plugs directly into the port of a vehicle.

Having a basic understanding of DTCs can be helpful for drivers and fleet managers. Read on to learn more about DTCs, how they work, and how you can read them.

Where do DTCs come from?

DTCs are generated by the vehicle’s on-board diagnostics (OBD) system whenever a fault is detected. The OBD both diagnoses the fault and displays the DTC through visible warnings such as the illumination of a check engine light. It is also what allows external devices, such as an OBD scanner, to interact with a vehicle’s onboard computer system.

 Over the years, several different versions of OBD interfaces were used—these interfaces, now classified as OBD-I, largely varied from manufacturer to manufacturer. Today, there are two main standards that people can use to read DTCs.

  • OBD2 -- best for light- and medium-duty vehicles

  • J1939 -- best for heavy-duty vehicles and heavy equipment

With the implementation of OBD-II, a standard DTC list  that contains codes that are common to all manufacturers was created by the Society of Automotive Engineers (SAE).

Though OBD-II is widely used, it is important to note that manufacturer-specific DTCs still exist. Manufacturers may create their own DTCs to supplement the list of universal codes if the vehicle requires it, but more often than not these manufacturer-specific codes are difficult to interpret without a mechanic.

Is your vehicle OBD-II or J1939 compliant?

OBD-II compliant:

  • Cars and light trucks built and sold in the United States after January 1, 1996 were required to be OBD-II equipped.

J1939 compliant:

  • Most diesel engine manufactured vehicles or equipment are J1939 compliant 

  • The industry standard for most heavy-duty trucks and buses

If you are unsure whether your vehicle is OBD-II or J1939 compliant, check your vehicle manual, research online, or consult with your dealership to confirm compatibility.

How do you read an OBD-II DTC?

DTC codes are five characters long. Each character in the DTC provides a different piece of information about the vehicle’s problem. 

The first character is always a letter. It indicates which control system has an issue, and has the following possible values and meanings:

  • P (powertrain) refers to the engine, transmission, fuel system, and associated accessories. 

  • C (chassis) refers to mechanical systems generally outside the passenger compartment such as steering, suspension, and braking.

  • B (body) refers to parts mainly found in the passenger compartment area. 

  • U (network) refers to the vehicle’s onboard computers and related systems.

The second character is a digit, typically 0 or 1, and shows whether or not the code is standardized. 

  • 0 indicates that the code is generic, standardized SAE (Society of Automotive Engineers) code. Generic codes are adopted by all cars that follow the OBD-II standard.

  • 1 indicates that the code is vehicle manufacturer-specific.These codes are unique to a specific car make or model and are typically less common. 

  • 2 or 3 are more rare and their meanings are dependent on the preceding letter of the code. Most of the time, 2 or 3 indicates that a code is manufacturer-specific, with only a few exceptions. 

The third character is also a digit, ranging from 1 to 8. This reveals the subsystem at fault.

  • 1 refers to the fuel or air metering system

  • 2 refers to the fuel or air metering injection system

  • 3 refers to the ignition system

  • 4 refers to the emissions system

  • 5 refers to the vehicle speed controls and idle control system

  • 6 refers to the computer output circuit

  • 7 and 8 indicate that the issue is transmission-related

The fourth and fifth characters are read together as a two-digit number between 0 and 99 known as the specific fault index. These characters identify the exact issue of the vehicle. 

If you are unsure about what your code means, check with your vehicle manufacturer or your vehicle manual for explanations.

Make compliance easy

Simplify compliance for your drivers and back office with intuitive, easy-to-use tools.

Learn More

How do you interpret a DTC?

Each DTC corresponds to a specific vehicle malfunction, such as a misfire in engine one. The following common DTC, P0128, would be read like this: 

  • The first letter is P, which means that the issue lies in the powertrain.

  • The second character is 0, indicating that the following code is not manufacturer-specific code. It is standardized and can be interpreted according to SAE definitions.

  • The third character is 1, which reveals that the issue is specifically within the fuel and air metering subsystem.

  • The last two digits make up the specific fault index 28. 

Based on this reading, it’s clear that code P0128 refers to an issue of the engine coolant temperature that’s below thermostat regulating temperature.

What are common DTCs?

Certain DTCs are more likely to appear than others. Below is a list of common DTCs you may encounter and their corresponding malfunctions.

  • P0442: A small system leak in a vehicle’s evaporative emission control system. 

  • P0606: A  malfunction in the power train control module (PCM), also known as the engine control module (ECM). 

  • P0101:  A fault in the mass air flow (MAF) sensor or circuit.

  • P0110: A malfunction in the intake air temperature sensor circuit.

  • P0500:  A vehicle speed sensor malfunction.

  • P0706: Fault in the transmission range sensor circuit range.

It is important to note that while DTC’s are useful in identifying a vehicle’s malfunction, they are not a way to decipher why the malfunction occurred. A vehicle needs to be further diagnosed by a mechanic to identify and address the cause of the issue.

How do you read a J1939 DTC?

A J1939 DTC contains four fields that relay information about the fault being reported by DTC. These fields are:

  1. Suspect Parameter Number (SPN): Represents the SPN with error. Every defined SPN can be used in a DTC.

  2. Failure Mode Identifier (FMI): Represents the nature and type of error that occurred, e.g., value range violation (high or low), sensor short-circuits, incorrect update rate, calibration error.

  3. Occurrence Counter (OC): A counter that counts the occurrence of the error condition for each SPN and stores this even when the error is no longer active.

  4. SPN Conversion Method (CM): Defines the byte alignment within the DTC. The value “0” represents the method shown in graphic “Structure of a DTC”. If CM has the value “1”, a distinction must be made between three previously valid methods; this must be known for the system.

DTC scan tools for fleet managers 

Scanners that read DTC, known as OBD-II scanners, are widely available for purchase. But if you’re a fleet manager responsible for numerous vehicles, having to manually check a vehicle every time the check engine light turns on can be inefficient. 

That’s why it’s important to select a fleet management solution, like Samsara, that includes maintenance tools that make identifying a DTC a fast and easy process. Samsara vehicle gateways plug in directly to the vehicle’s OBD-II port and send vehicle-related data—including DTCs—to the cloud. This means if a DTC occurs, it will automatically populate in your Samsara Dashboard or you can choose to be notified via an alert.

In the event that several of your fleet vehicles experience DTC issues, a telematics solution that includes a DTC tool can help you quickly identify what the issue is so you can quickly take appropriate steps to schedule maintenance as needed. 

Understand DTCs easily with telematics

Seeing an illuminated check engine light without knowing the reason behind it can be troublesome. That’s why it’s important to find a telematics solution, like Samsara, that helps you understand DTC so you can identify your vehicle’s issue and take action accordingly.

The Samsara vehicle gateway plugs directly into the OBD-II or the J1939 port of a vehicle and can thus relay any information regarding any DTC directly to the Samsara Dashboard. Furthermore, alerts can be triggered in the event that a DTC occurs by using the "Vehicle Fault" alert. You can also use Samsara’s DTC filtering feature to get alerts for the DTCs that matter most to your fleet.

For more information about how Samsara can help you read and address DTCs, sign up for a free trial or learn more about Samsara’s fleet maintenance solutions.

Sours: https://www.samsara.com/guides/dtc-codes

How to Read and Understand Check Engine Light (OBD-II) Codes

The Check Engine Light turning on is usually a topic car owners try to avoid talking too much about. It can be quite intimidating to see that little light on your vehicle’s dashboard suddenly illuminate, but in reality, it is not something that should paralyze you in fear right away. By preparing yourself with a little automotive knowledge, a helpful tool, and general background information on what this light is actually trying to tell you, you will not only gain more peace of mind, you will also develop a closer relationship to your vehicle.

Diagnostic trouble codes (DTC) are automotive computer codes stored by the on-board computer diagnostic system (OBD) in your vehicle. There are literally hundreds of different codes a Check Engine Light can represent. While that sounds daunting, with a little patience, tackling basic diagnostics will give you useful knowledge about your vehicle and will also allow that Check Engine Light to do what it is really supposed to do: be your guide.

There are two acronyms to be aware of when it comes to discovering more about Check Engine Lights. These two acronyms are OBD and DTC.

  • Tip: OBD codes refers to nearly the same thing as DTC codes, therefore you will often hear them used interchangeably in the automotive industry. OBD codes are most frequently referred to as OBD-II, which has been the code type since 1996.

OBD acronym table

Unfortunately, obvious and helpful vehicle symptoms do not always accompany an illuminated Check Engine Light. Since there are hundreds of possible OBD codes, there are also hundreds of possible reasons for the light, including:

  • Computer output circuit issues
  • Emissions controls issues
  • Fuel and air metering systems problems
  • Ignition system faults
  • Speed control and idle problems
  • Transmission issues

This is why it is important for someone who does not have a lot of automotive knowledge to not assume what a code means. When your Check Engine Light comes on, you should get it checked out quickly by a certified mechanic. If the engine light comes on due to a serious concern, you risk damaging your car further by not repairing the issue right away.

  • Warning: If the Check Engine Light comes on and flashes, it indicates a very serious concern. Find a safe place to stop, turn off your car, and have it diagnosed and repaired before you continue to use it.

Inserting and Reading an OBD Scanner

Your Check Engine Light is illuminated when a fault is detected with one of your vehicle’s monitored systems. In order to find out the reason the light is illuminated, you need to read the codes through the OBD port.

You will need an OBD scan tool. The scanner allows you to communicate with the computer and retrieve the trouble codes. Certain scanners may give information on what the revealed code means, but most will just give a five digit number and letter combination.

Follow these 4 steps to insert and read the OBD scanner:

OBD port at bottom of glove box

Step 1: Locate your vehicle’s OBD port. The most common mounting location for an OBD port is under the driver’s side of the dash near the pedals.

It legally has to be within 3 feet of the steering wheel and must not require tools to access it.

The connector is a female 16-pin connector that is trapezoidal in shape.

plugging in connector male to female

Step 2: Plug your OBD scan tool into the connector. The scan tool’s male end will only fit one way onto the vehicle’s connector.

The scan tool will power up as soon as it has been plugged in.

obd scanner shown

Step 3: Read the codes in the computer. Each scan tool will have different instructions on how to operate it, so read yours carefully.

Navigate to a heading called “Read Codes” and select it.

scanner showing code

Step 4: Record the codes that display. If there are multiple codes, they may cycle through or you may have to press a button to view the next code.

  • Tip: It is very important to write these codes down in the same order as displayed on the scanner. However, the OBD codes will always appear on your scanner when it is plugged into the OBD port or data link connector (DLC).

Interpreting OBD Codes

OBD codes may seem complex, but underneath the letters and numbers, you can identify the general cause of your lit Check Engine Light, allowing you to take the next necessary steps.

chart explaining how to read codes

Step 1: Break down your code into sections.

1. The first section is the first character, which is always a letter.

2. The second section is the next character, which is a single number, from 0 to 3.

3. The third section is the third character, which is a single number from 0 to 9.

4. The fourth and last section includes both the fourth and fifth characters together, so it is a pair of numbers, from 00 to 99.

Step 2: Determine the meaning of the letter. There are four possible letters that can be displayed in the first section.

chart of some possible P codes

The letter “P” indicates powertrain-related codes such as those involving the engine or the transmission and their sensors. Typically, “P” codes are the only ones that will illuminate the Check Engine Light.

possible B codes

The letter “B” indicates a body code, which means that it relates to a body system such as the airbags.

chart of some possible C codes

The letter “C” indicates a chassis code, used for systems such as the anti-lock brakes.

possible U codes

The letter “U” indicates network codes which are used for problems like module failures and losses of communication.

  • Note: Only professional-grade or dealership scan tools are able to diagnose codes outside of powertrain codes.

generic vs manufacturer codes

Step 3: Determine if the codes are Society of Automotive Engineers (SAE) codes or manufacturer-specific. This is indicated by the first number in the sequence, immediately after the letter.

SAE codes are generic codes that apply to all makes and models. SAE codes are indicated with a “0” as the second digit.

Manufacturer-specific codes use a number other than “0” as the second digit.

In general, codes that begin with P0 are generic codes concerning a powertrain issue, whereas codes that begin with P1 are manufacturer-specific.

Step 4: Determine which system the code applies to. The third number in the sequence refers to the system that is affected:

  • A “1” indicates a fuel or air metering system problem, such as an issue with the mass air flow sensor.

  • A “2” refers to fuel or air metering injection system issues, such as a fuel injector problem.

  • A “3” indicates an ignition-related problem, such as an engine misfire.

  • A “4”refers to emissions system problems, like a catalytic converter efficiency issue.

  • A “5” indicates vehicle speed controls and idle control system problems.

  • A “6” refers to computer output circuit issues, like an internal computer failure.

  • The numbers “7”, “8”, or “9” all indicate transmission-related problems, like pressure faults and sensor failures.

Step 5: Determine the exact fault. The last two numbers provide a description of the fault code. To read the description for your specific trouble code, check an online source such as OBD-Code’s website.

  • Tip: You will want to address the top DTCs first if there are multiple codes. In some cases, the codes lower down on the list may be symptoms of a code higher up on the list.

It is important to remember that any code revealed is only a starting point for proper diagnosis. An OBD code will only indicate the system experiencing the issue; it will not tell you why or how to fix it. Oftentimes, parts are replaced over and over until it is made clear that a code does not equal the part. Codes can also be generated due to temporary problems, such as a loose fuel cap, a poor connection, or even moisture affecting one of the many sensors’ readings. While determining a code may just be the starting point, it is fundamental, and taking these first steps will help you to learn more about your vehicle and let it be your guide.



The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Sours: https://www.yourmechanic.com/article/how-to-read-and-understand-check-engine-light-codes-by-jason-unrau

Meaning car codes

Diagnostic Trouble Codes Explained

  • 26 April 2017
  • Auto Doctor
  • Tutorial

Editor's note: This post has been updated in March 2020 for accuracy and the latest information.

Diagnostic Trouble Codes or OBD2 Trouble Codes are codes that the car’s OBD system uses to notify you about an issue. Each code corresponds to a fault detected in the car. When the vehicle detects an issue, it will activate the corresponding trouble code.

A vehicle stores the trouble code in it’s memory when it detects a component or system that’s not operating within acceptable limits. The code will help you to identify and fix the issue within the car.

Each trouble code consists of one letter and four digits, such as P1234. This blog post will teach you how to interpret the meaning of the codes.

Format of the OBD2 Trouble Codes

System or Category

The OBD2 Trouble Codes are categorised into four different systems.

  • Body (B-codes) category covers functions that are, generally, inside of the passenger compartment. These functions provide the driver with assistance, comfort, convenience, and safety.

  • Chassis (C-codes) category covers functions that are, generally, outside of the passenger compartment. These functions typically include mechanical systems such as brakes, steering and suspension.

  • Powertrain (P-codes) category covers functions that include engine, transmission and associated drivetrain accessories.

  • Network & Vehicle Integration (U-codes) category covers functions that are shared among computers and systems on the vehicle.

The first letter of the code will mark the system related to the trouble code.

Generic and manufacturer specific codes

The first digit in the code will tell you if the code is a generic or manufacturer specific code.

Codes starting with 0 as the first digit are generic or global codes. It means that they are adopted by all cars that follow the OBD2 standard. These codes are common enough across most manufacturers so that a common code and fault message could be assigned.

Codes starting with 1 as the first digit are manufacturer specific or enhanced codes. It means that these codes are unique to a specific car make or model. These fault codes will not be used generally by a majority of the manufacturers.

The first digit might be also 2 or 3. In this case the type depends on the system. B2xxx and C2xxx codes are manufacturer controlled while B3xxx and C3xxx codes are reserved at the moment. P2xxx codes are generic codes while P3xxx codes are manufacturer controlled. U2xxx codes are manufacturer controller as well as U3xxx codes.

Subsystem or functional area

Previously, the second digit defined the sub-system of the codes. However, the latest document defining the diagnostic trouble codes (J2012 revised in 2016-12) had some changes to this.

According to the document, as the DTC usage has increased with the introduction of new technology to vehicle systems, it was necessary to remove the grouping of DTCs into functional areas.

Fault description

The last two or nowadays three digits define the actual fault description. These numbers will tell the particular problem and each code is defined separately. There’s no formula to decode these codes automatically.

Luckily, OBD Auto Doctor software contains the fault description for over 18 000 diagnostic trouble codes.

Learn more

There’s no need to memorize the format of the codes because you can read the codes with the free version of the OBD Auto Doctor car diagnostic software.

If your car has the Check Engine Light on, it means that the vehicle has one or more confirmed OBDII trouble codes active. To learn




Sours: https://www.obdautodoctor.com/scantool-garage/diagnostic-trouble-codes-explained
Diagnostic Trouble Code DTC

Have you heard of this. Yes, she whispered. You will, bye, my mistress. I will fuck like the very last whore, anytime, anywhere, wherever I want. In this I am god.

You will also like:

Petersburg next weekend, she did her best and also got herself a business trip to St. Petersburg. Naturally, I found out about this at the very beginning of the week and began to prepare for our trip together, without saying a. Word to Oksana.



15771 15772 15773 15774 15775