DTC codes
Look up an OBD-II fault code: what it means on every car or on your make, and how to track it down.
How to read a code
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 4
- AreaAuxiliary emission controls
- 20
- FaultThe specific fault in that area
Read the code
Note every stored and pending code your scanner shows, such as P0420.
Find it
Search by code or by words. For a manufacturer code (P1, B1, C1, U1) pick your make: its meaning differs by make.
Open the code
Its page explains the symptoms, likely causes, the checks to run and the fixes.
- P04F5Generic · PowertrainCatalyst Heater Circuit Low Bank 2
- P04F6Generic · PowertrainCatalyst Heater Circuit High Bank 1
- P04F7Generic · PowertrainCatalyst Heater Circuit High Bank 2
- P04F8Generic · PowertrainCatalyst Heater Circuit Intermittent Bank 1
- P04F9Generic · PowertrainCatalyst Heater Circuit Intermittent Bank 2
- P04FAGeneric · PowertrainEGR A Control Temperature Too High
- P04FBGeneric · PowertrainCrankcase Ventilation Hose Connection Sensor Range/Performance
- P04FCGeneric · PowertrainCrankcase Ventilation System Performance
- P04FDGeneric · PowertrainEGR Actuator A Control Processor Performance
- P04FEGeneric · PowertrainCatalyst Heater Circuit Performance Bank 1
- P04FFGeneric · PowertrainCatalyst Heater Circuit Performance Bank 2
- P0500Generic · PowertrainVehicle Speed Sensor A Circuit
- P0500Audi · PowertrainDefective Vehicle Speed Sensor, Defective Speedometer, Vehicle Speed Sensor wiring or connector, Communication (CAN) bus problems, Defective transmission or differential Vehicle Speed Sensor drive gear
- P0501Generic · PowertrainVehicle Speed Sensor A Circuit Range/Performance
- P0501Audi · PowertrainDefective Vehicle Speed Sensor, Defective Speedometer, Vehicle Speed Sensor wiring or connector, Communication (CAN) bus problems, Defective transmission or differential Vehicle Speed Sensor drive gear
- P0502Generic · PowertrainVehicle Speed Sensor A Circuit Low
- P0503Generic · PowertrainVehicle Speed Sensor A Circuit Intermittent/Erratic/High
- P0504Generic · PowertrainBrake Switch A/B Correlation
- P0505Generic · PowertrainIdle Control System
- P0505Audi · PowertrainDefective Idle Air Control Motor, Intake Manifold Vacuum leaks, Carbon buildup in the Throttle Body air passages
- P0506Generic · PowertrainIdle Control System RPM - Lower Than Expected
- P0506Audi · PowertrainDefective or sticking Idle Air Control Motor, Intake Manifold Vacuum leaks, Carbon buildup in the Throttle Body air passages, Defective Power Steering Pressure Switch
- P0507Generic · PowertrainIdle Control System RPM - Higher Than Expected
- P0507Audi · PowertrainDefective or sticking Idle Air Control Motor, Intake Manifold Vacuum leaks, Carbon buildup in the Throttle Body air passages, Defective Coolant Temperature Sensor, Defective Charging System/Alternator, Defective Power Steering Pressure Switch
- P0508Generic · PowertrainIdle Air Control System Circuit Low
- P0509Generic · PowertrainIdle Air Control System Circuit High
- P050AGeneric · PowertrainCold Start Idle Control System Performance
- P050BGeneric · PowertrainCold Start Ignition Timing Performance
- P050CGeneric · PowertrainCold Start Engine Coolant Temperature Performance
- P050DGeneric · PowertrainCold Start Rough Idle
