Fault Codes – The Most Common Codes with Prompt Explanation

Fault codes are an important factor for DIY car diagnostics. You can inspect your vehicle using a cheap scanner and avoid paying $150-$200 for this inspection in a dealership. But you need to understand what a certain code means, where it can be stored, and which exact issues may trigger this code.

In this article, I will tell you about all the error codes that I described here, at Cararac.com and give the links to the full articles. You may investigate the problem deeply before you make any certain solution about the repairs.

480A code

The 480A code is very common for older diesel cars and it means that there are issues with the DPF. It may be clogged, broken, or require regeneration. This code can also mean that emissions sensors are sending the wrong signals to the ECU.

480A code highlights:

• Level of urgency:Low
• Possible culprits:DPF, emission sensors, exhaust anomalies
• Price for repair:$100 - $950
• If neglected:Further DPF damage, no chance to pass the emission test
• DIY repairs:Possible in some vehicles
• Can you drive?Yes

55C3 code

While in most cases the 55C3 code is triggered by some minor issue like a bad ABS sensor on one of the wheels or issues with wiring, it originally means problems with AWD. So, it can mean that there are issues with your transfer case or differential. The vehicle needs proper inspection.

55C3 code highlights:

• Level of urgency:High
• Possible culprits:AWD issues, wheel speed sensor, wiring problems
• Price for repair:$150 - $1,400
• If neglected:AWD damage, wheels lockup, no AWD available
• DIY repairs:Impossible
• Can you drive?Carefully

7E8 code

The 7E8 code will mean that there is a problem registered by the Engine Control Module. It doesn't mean a certain problem like fuel supply issues or ignition problems. It just informs you that there are other issues and codes that require inspection.

7E8 code highlights:

• Level of urgency:Medium
• Possible culprits:Anykind ofproblems with engine management system
• Price for repair:$50 - $500
• If neglected:Engine limp mode, electrical issues, problems escalating
• DIY repairs:Possible but complicated
• Can you drive?Carefully

B0081 code

If you see the B0081 code, it doesn't mean that there are issues with the engine or transmission. The problem is with the system that detects if there is a person in the seat. To understand which seat is affected, you will need to read other codes or use a professional scanner for clarification.

B0081 code highlights:

• Level of urgency:Medium
• Possible culprits:Passenger detection system sensor broken or disconnected
• Price for repair:$50 - $350
• If neglected:Airbags may not deploy when needed
• DIY repairs:Impossible
• Can you drive?Yes

B123 code

The meaning of the B123 code may differ according to your vehicle model and also maintenance routine. Usually, dealership mechanics can get more information with a professional scanner. It may mean the interval for the oil change, tire rotation, valve adjustment, or whatever.

B123 code highlights:

• Level of urgency:Medium
• Possible culprits:The car is about to hit one of the maintenance intervals
• Price for repair:$100 - $450
• If neglected:Poor maintenance may kill your vehicle fast
• DIY repairs:Possible
• Can you drive?Yes

C0561-71 code

The C0561-71 code means that your ABS or traction control system requires service. In most cases, this is a minor issue like a broken ABS sensor or a wire that has fallen off. But sometimes, it may also mean other problems that are hard to locate.

C0561-71 code highlights:

• Level of urgency:Medium
• Possible culprits:Issues with ABS or traction control systems
• Price for repair:$100 - $350
• If neglected:ABS may not be working, traction control may not be active
• DIY repairs:Impossible
• Can you drive?Carefully

C0800-03 code

The C0800-03 code means that there are problems with voltage on the PCM or powertrain control module. Usually, this happens because of 12V battery problems, alternator issues, or bad PCM. Professional inspection may be needed.

C0800-03 code highlights:

• Level of urgency:High
• Possible culprits:Voltage problems, PCM issues, wiring issues
• Price for repair:$150 - $750
• If neglected:Different glitches may show up
• DIY repairs:Impossible
• Can you drive?Yes

P0012/P0014 code

When you see the P0012 code, it means that the variable valve timing solenoid is probably faulty. The ECU sees that the camshaft is in the wrong position and generates this code. In some cases, the problem may also be with the worn-out camshaft. The same is true for the P0014 code - this specifically means that the camshaft timing is over-advanced.

P0012/P0014 code highlights:

• Level of urgency:Medium
• Possible culprits:VVT solenoid problems, camshaft issues
• Price for repair:$300 - $1,000
• Ifneglected:Engine will work harshly and ineffectively
• DIY repairs:Impossible
• Can you drive?Not for long

P0016/P0017 code

Whenever you see the P0016 or P0017 code in your vehicle, you may be sure that the timing of the crankshaft isn't perfectly aligned with the timing of the crankshaft. Alternatively, there may be a problem with one of the sensors telling the ECU about their positions.

P0016/P0017 code highlights:

• Level of urgency:Medium
• Possible culprits:crankshaft or camshaft issues, position sensor problems
• Price for repair:$350 - $2,500
• Ifneglected:Engine will work harshly and ineffectively
• DIY repairs:Impossible
• Can you drive?Not recommended

P0051 code

The P0051 trouble code shows that there is a problem with the oxygen sensor (O2 sensor). It's located near your catalytic converter and verifies that the maximum possible amount of oxygen is burnt during engine work. It may be overheated or just dead.

P0051 code highlights:

• Level of urgency:Medium
• Possible culprits:oxygen sensor overheated or dead
• Price for repair:$500 - $1,200
• If neglected:Emission problems, fuel consumption issues, harsh work of the engine
• DIY repairs:Possible but complicated
• Can you drive?Yes

P0087 code

With the P0087 code, it's most likely that the fuel pressure is lower than expected. This may mean that the fuel pump is not working at its full potential. Also, the code may mean that there is a blockage in the fuel lines or the fuel filter is clogged. Sometimes, the problem is in the fuel pressure sensor malfunctioning and throwing this error code. Also, the P0089 code shows the same problem.

P0087 code highlights:

• Level of urgency:High
• Possible culprits:fuel pump, fuel filter, fuel lines, fuel pressure sensor
• Price for repair:$100 - $800
• If neglected:Engine may not work efficiently, fuel pressure may fall evenfurther
• DIY repairs:Impossible
• Can you drive?Carefully

P0093 code

The P0093 code is pretty common for vehicles with direct injection systems. This means that the electronic control unit suspects there is a significant fuel leak and the fuel is pouring out. Of course, driving like this is not recommended, this may eventually lead to fire or total fuel loss.

P0093 code highlights:

• Level of urgency:High
• Possible culprits:fuel leak, fuel pump problem, fuel lines issues, clogged fuel filter
• Price for repair:$100 - $550
• If neglected:Fire is possible, fuel loss can happen
• DIY repairs:Impossible
• Can you drive?Not recommended

P0118 code

The P0118 error code means that there are issues with the engine coolant temperature. It may not send its readings to the ECU or its readings may be completely out of the usual range. Usually, it means that the sensor needs replacement or there is some issue with wiring.

P0118 code highlights:

• Level of urgency:High
• Possible culprits:engine coolant temp sensor dead, wiring problems
• Price for repair:$50 - $250
• If neglected:You won't know if the engine overheats
• DIY repairs:Possible
• Can you drive?Carefully

P0128 code

When your engine is running significantly colder than it should be, your ECU will throw the P0128 code. This means that the thermostat may not be working properly or there are issues with the temperature sensors and their readings.

P0128 code highlights:

• Level of urgency:High
• Possible culprits:thermostat problems, issues with engine coolant temp sensors
• Price for repair:$100 - $450
• If neglected:Engine won't work efficiently
• DIY repairs:Possible but complicated
• Can you drive?Carefully

P0134/P0135 code

If the oxygen sensor (the first one) malfunctions, you may see the P0134 code when scanning for errors. This code means that there are issues with the sensor itself or with the wiring. Usually, sensor replacement helps but other possible culprits should be checked first. This code means the same as P0135, just with some technical differences.

P0134/P0135 code highlights:

• Level of urgency:Medium
• Possible culprits:oxygen sensor1is malfunctioning, wiring problems
• Price for repair:$150 - $600
• If neglected:Fuel consumption growth, harsh work of the engine, failing emission test
• DIY repairs:Possible but complicated
• Can you drive?Yes

P0171 code

The P0171 error code means that the ECU detected an incorrect ratio between fuel and air that entered the engine. There is too much air (due to some vacuum leaks) or too little fuel (due to fuel pump issues or a clogged filter, for example). Hence the air-fuel mixture is not correct.

P0171 code highlights:

• Level of urgency:Medium
• Possible culprits:MAF sensor, fuel pump, clogged filters, vacuum leaks
• Price for repair:$150 - $400
• If neglected:Harsh work of the engine, high fuel consumption, engine damage
• DIY repairs:Possible
• Can you drive?Carefully

P0234 code

The P0234 code means overboost. This happens when the turbocharger blows in too much air and the engine can't cope with the pressure. The problem leads to inefficient engine work, sputtering, or even stalling. Usually, the turbocharger or the piping is in charge.

P0234 code highlights:

• Level of urgency:Medium
• Possible culprits:Turbocharger problems, piping issues, sensor problems
• Price for repair:$100 - $800
• If neglected:No power, harsh engine work, anomalies with fuel consumption
• DIY repairs:Impossible
• Can you drive?Carefully

P0299 code

The P0299 code means turbocharger underboost. So, the air pressure from the turbocharger is lower than expected by the sensors. It may mean that the turbocharger itself is broken. Also, this code may pop up when there are broken or cracked pipes, fallen-off connections in the turbocharger piping, etc. So, you will need to look for air leaks in the system. If the turbocharger is old enough, it may mean that there are internal problems with the unit and the P0299 error code just means you need to repair or replace it.

P0299 code highlights:

• Level of urgency:Medium
• Possible culprits:Turbocharger issues, fallen off or cracked pipes, air leak problems
• Price for repair:$150 - $800
• If neglected:Loss of power, harsh work, poor efficiency
• DIY repairs:Impossible
• Can you drive?Carefully

P0300 code

Whenever you see the P0300 code on your scanner's screen, you may be sure that your engine is misfiring. Exactly the P0300 trouble code means that the misfiring occurs in various cylinders or the sensors can't catch which exact cylinder causes problems.

Also, the P0300 code may have several variations. The number in the end may mean a certain cylinder. For example, the P0303 code will mean that the misfiring occurs in the cylinder 3.

P0300 code highlights:

• Level of urgency:Medium
• Possible culprits:Bad plugs, bad coils, issues with fuel supply, air supply problems
• Price for repair:$100 - $550
• If neglected:Loss of power, harsh work, inefficient fuel consumption, vibrations
• DIY repairs:Possible but complicated
• Can you drive?Yes

P0330 code

If you see the P0330 code on your scanner, it means that the knock sensor in your engine has problems. It doesn't exactly mean that there are knocking issues inside the engine. It just means that the knock sensor's circuit has anomalies and wiring or the sensor itself should be checked.

P0330 code highlights:

• Level of urgency:Low
• Possible culprits:Knocking, knock sensor issues, wiring problems
• Price for repair:$150 - $250
• If neglected:Engine knocking, knock sensor inoperable
• DIY repairs:Possible
• Can you drive?Yes

P0340 code

The P0340 error code means that the circuit of the camshaft position sensor is faulty. It may mean that the sensor itself needs replacement. Or there may be some problems with the wiring. Driving with such a code is not really safe for your engine, so better deal with the issue before you continue driving. Usually, the P0341 error code means the same.

P0340 code highlights:

• Level of urgency:High
• Possible culprits:Camshaft position sensor, wiring
• Price for repair:$200 - $350
• If neglected:Engine damage, uneven work of the engine
• DIY repairs:Possible
• Can you drive?Not recommended

P0401 code

The P0401 code means that the EGR doesn't allow the proper airflow into the engine. In most cases, this may mean that the EGR valve is clogged or stuck. While sometimes cleaning may help, in most cases, in a lot of cases, you will need the valve replacement. Also, the P0406 code means the EGR system needs repair or replacement.

P0401 code highlights:

• Level of urgency:Medium
• Possible culprits:EGR valve problems
• Price for repair:$200 - $800
• If neglected:Bad efficiency, harsh work, loss of power
• DIY repairs:Impossible
• Can you drive?Carefully

P0420 code

Whenever you see the P0420 code, you may be sure that the problem is with the catalytic converter. It may mean that the converter is clogged or damaged. The gases may not flow through the converter efficiently, so it will require replacement. Unfortunately, this is pretty expensive. Also, with this code, you aren't likely to pass any emission test.

Also, the P0430 code means that the catalytic converter isn't working efficiently enough.

P0420 code highlights:

• Level of urgency:Medium
• Possible culprits:catalytic converter, exhaust pipe
• Price for repair:$500 - $1,500
• If neglected:Engine stalling, power loss, failing emission tests
• DIY repairs:Impossible
• Can you drive?Yes

P0449 code

When you see the P0449 code, you may understand that the evaporative control system or EVAP in your car is faulty. This is the canister with charcoal that filters the air coming out of the tank. The system is durable but when it fails, it requires replacement. Sometimes, piping may need reinstalling due to air leaks.

Also, the P0457 code may mean leaks in the EVAP system. While the P0496 code will usually mean that there is a problem with the purge valve in the evaporative system.

P0449 code highlights:

• Level of urgency:Low
• Possible culprits:EVAP system, purge valve, piping, air leaks
• Price for repair:$150 - $600
• If neglected:Harsh engine work, lower efficiency
• DIY repairs:Possible but complicated
• Can you drive?Yes

P06DE code

The unusual P06DE code means that there are problems with oil pressure. In most cases, the culprit for this is the fuel pump but you should make a certain investigation. First of all, the oil pressure sensor may malfunction. Additionally, there may be issues with the oil level.

P06DE code highlights:

• Level of urgency:High
• Possible culprits:Oil pump, oil pressure sensor, low oil level
• Price for repair:$150 - $450
• If neglected:Poor lubrication and engine death
• DIY repairs:Possible but complicated
• Can you drive?Not recommended

P0700 code

The P0700 code means that there are issues with your transmission control module. It doesn't usually mean that the transmission malfunctions (although it can, of course), but the TCU itself is having a hard time. Wiring and software should be checked before replacing the expensive module.

P0700 code highlights:

• Level of urgency:High
• Possible culprits:TCU, transmission
• Price for repair:$350 - $4,500
• If neglected:Transmission death, TCU death
• DIY repairs:Impossible
• Can you drive?Very carefully

P0706 code

If you see the P0706 code, it clearly tells you that there is a problem with the transmission range sensor. It may malfunction or be disconnected. Sometimes, this problem is triggered by the shifter sensor. Before you install any new sensor, proper inspection is needed with professional scan tools.

P0706 code highlights:

• Level of urgency:High
• Possible culprits:Transmission range sensor, wiring
• Price for repair:$150 - $500
• If neglected:Limp mode, no shifting
• DIY repairs:Possible but complicated
• Can you drive?Yes, if it drives

P1326 code

In various vehicles, the P1326 code means that the knock sensor has detected problems with vibrations inside your engine. This may tell you about rod bearing wear or some other internal problem. Ignoring this issue is obviously not the best option for you.

P1326 code highlights:

• Level of urgency:Medium
• Possible culprits:Rod bearing, piston wear, connections in the engine
• Price for repair:$1,000 - $3,000
• If neglected:Engine damage
• DIY repairs:Impossible
• Can you drive?Carefully

P132B code

In most cases, the P132B code means that there are issues with the air supply in your engine. Mainly, the engine registers higher or lower air pressure than needed. This may be caused by a vacuum leak, air leak, or faulty MAF sensor, for example.

P132B code highlights:

• Level of urgency:Medium
• Possible culprits:MAF sensor, air leak, vacuum leak
• Price for repair:$100 - $350
• If neglected:Loss of power, unstable work
• DIY repairs:Possible
• Can you drive?Yes

P2015 code

Whenever you see the P2015 code in your vehicle, there are chances that the intake manifold is broken, cracked, or has other problems. While the code itself says about the intake manifold runner control issues, it may tell you about other problems with the intake system as well.

P2015 code highlights:

• Level of urgency:Medium
• Possible culprits:Intake manifold
• Price for repair:$50 - $350
• If neglected:Harsh engine work, loss of power
• DIY repairs:Possible
• Can you drive?Yes

P207F code

In most cases, the P207F code is seen in diesel vehicles and tells you about the DEF system problems. Maybe, the DEF tank is empty, or there are issues with the DEF injection. If you see this is a gas-driven vehicle, this may be the death of the catalytic converter or an emission sensor.

Basically, the P20EE code has the same meaning that also means issues with the DEF and sometimes may substitute the previously mentioned code.

P207F code highlights:

• Level of urgency:Medium
• Possible culprits:DEF system, catalytic converter, emission sensors
• Price for repair:$50 - $1,000
• If neglected:Limp mode, failing of emission test
• DIY repairs:Possible but may be complicated
• Can you drive?Yes

P2097 code

Whenever you see the P2097 code, you may be sure that the fuel isn't totally combusted in your engine and it gets into the exhaust system. This code means the ignition, air supply, and fuel supply systems should be carefully checked.

P2097 code highlights:

• Level of urgency:Medium
• Possible culprits:Fuel supply, air supply, ignition system, emission sensors
• Price for repair:$300 - $600
• If neglected:Failing emission test, dead catalytic converter, poor efficiency
• DIY repairs:Impossible
• Can you drive?Yes

P2106 code

Usually, the P2106 code is part of the problem and it shouldn't be the only available code. This means that your car has gone to limp mode or limp home mode. This means that the engine power has been reduced or the maximum speed has been limited. Also, there should be other codes and problems that triggered the limp mode.

P2106 code highlights:

• Level of urgency:High
• Possible culprits:Any problems with the engine or transmission
• Price for repair:$50 - $5,000
• If neglected:Engine problems, transmission problems
• DIY repairs:Impossible
• Can you drive?Yes

P2263 code

Usually, the P2263 code means that there are issues with the turbocharger system in your vehicle. In most cases, this means that the efficiency of turbo boost is low. This may be because of the turbocharger death or some leaks due to piping problems.

P2263 code highlights:

• Level of urgency:Medium
• Possible culprits:Turbocharger, turbo piping
• Price for repair:$0 - $650
• If neglected:Loss of power, inefficient work
• DIY repairs:Impossible
• Can you drive?Carefully

P2422 code

When you see the P2422 code on the OBD2 scanner, there is a chance that the EVAP canister has a problem with its vent valve. So, the breather may be stuck closed and now no fresh air can go into the tank. This affects the work of the fuel pump.

P2422 code highlights:

• Level of urgency:High
• Possible culprits:EVAP canister vent valve problems
• Price for repair:$150 - $250
• If neglected:Emission codes and alerts, vacuum in fuel tank, fuel pump problems
• DIY repairs:Impossible
• Can you drive?Not for long

P242F code

The P242F code is connected with the work of the DPF or Diesel Particulate Filter. This code means that the filter is full of ash and particles and requires regeneration. You may try to launch manual regeneration if possible or drive on the highway at high RPM for some time. Otherwise, the DPF may get totally clogged soon.

P242F code highlights:

• Level of urgency:High
• Possible culprits:DPF full, regeneration needed
• Price for repair:$0 - $800
• Ifneglected:DPF will get fatally clogged
• DIY repairs:Impossible
• Can you drive?Yes

P2459 code

The P2459 error code means that the frequency of the regeneration procedures wasn't desired. This means that the regen may have started too often and this may also mean that the DPF is not in its best condition. The P2459 code will most likely mean that the DPF requires manual regen or even replacement.

P2459 code highlights:

• Level of urgency:Medium
• Possible culprits:DPF full, regeneration needed
• Price for repair:$0 - $800
• If neglected:DPF may require replacement soon
• DIY repairs:Impossible
• Can you drive?Yes

P2647 code

The P2647 code is a common problem for VTEC engines in Honda and Acura cars. This means that there are problems with the rocker arm actuators. Basically, this may mean almost any problems with the VTEC system, and your valves may open and close at the wrong time.

P2647 code highlights:

• Level of urgency:High
• Possible culprits:VTEC system problems
• Price for repair:$200 - $650
• Ifneglected:Engine won't work with its full potential
• DIY repairs:Impossible
• Can you drive?Carefully

P26A5 code

This is the specific code which means that there is a problem with the Thermo-Control Valve. In different vehicles, this issue may come from various problems. It's really common in Subaru vehicles in 2019-2021 but the problem can also affect other car brands.

P26A5 code highlights:

• Level of urgency:High
• Possible culprits:TCV issues, cooling system problems
• Price for repair:$150 - $300
• If neglected:Coolant level drop,badengine cooling
• DIY repairs:Impossible
• Can you drive?Yes

U112300 code

The U112300 code usually means that the ABS module starts sending weird signals to other control units in your car that it isn't supposed to send. This may mean ABS problems or some other communication or wiring issues in your vehicle.

U112300 code highlights:

• Level of urgency:Medium
• Possible culprits:ABS problems, communication problems
• Price for repair:$100 - $350
• If neglected:ABS not working, other glitches
• DIY repairs:Impossible
• Can you drive?Carefully

ISO9141 code

If you get the ISO9141 code on your code scanner, it doesn't mean that your vehicle has problems. It rather means that the scanner isn't connected properly or it's just not compatible with your vehicle.

ISO9141 code highlights:

• Level of urgency:Low
• Possible culprits:Scanner isbadlyconnected or not compatible
• Price for repair:$0
• If neglected:No codes will be detected
• DIY repairs:Possible
• Can you drive?Yes