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.
- P20A4Generic · PowertrainReductant Purge Control Valve A Stuck Open
- P20A5Generic · PowertrainReductant Purge Control Valve A Stuck Closed
- P20A6Generic · PowertrainReductant Injection Air Pressure Control Valve Circuit/Open
- P20A7Generic · PowertrainReductant Injection Air Pressure Control Valve Performance
- P20A8Generic · PowertrainReductant Injection Air Pressure Control Valve Circuit Low
- P20A9Generic · PowertrainReductant Injection Air Pressure Control Valve Circuit High
- P20AAGeneric · PowertrainReductant Injection Air Pressure Control Valve Stuck Open
- P20ABGeneric · PowertrainReductant Injection Air Pressure Control Valve Stuck Closed
- P20ACGeneric · PowertrainReductant Metering Unit Temperature Sensor Circuit
- P20ADGeneric · PowertrainReductant Metering Unit Temperature Sensor Circuit Range/Performance
- P20AEGeneric · PowertrainReductant Metering Unit Temperature Sensor Circuit Low
- P20AFGeneric · PowertrainReductant Metering Unit Temperature Sensor Circuit High
- P20B0Generic · PowertrainReductant Metering Unit Temperature Sensor Circuit Intermittent/Erratic
- P20B1Generic · PowertrainReductant Heater Coolant Control Valve Circuit/Open
- P20B2Generic · PowertrainReductant Heater Coolant Control Valve Performance/Stuck Open
- P20B3Generic · PowertrainReductant Heater Coolant Control Valve Circuit Low
- P20B4Generic · PowertrainReductant Heater Coolant Control Valve Circuit High
- P20B5Generic · PowertrainReductant Metering Unit Heater Control Circuit/Open
- P20B6Generic · PowertrainReductant Metering Unit Heater Control Circuit Performance
- P20B7Generic · PowertrainReductant Metering Unit Heater Control Circuit Low
- P20B8Generic · PowertrainReductant Metering Unit Heater Control Circuit High
- P20B9Generic · PowertrainReductant Heater A Control Circuit/Open
- P20BAGeneric · PowertrainReductant Heater A Control Circuit Performance
- P20BBGeneric · PowertrainReductant Heater A Control Circuit Low
- P20BCGeneric · PowertrainReductant Heater A Control Circuit High
- P20BDGeneric · PowertrainReductant Heater B Control Circuit/Open
- P20BEGeneric · PowertrainReductant Heater B Control Circuit Performance
- P20BFGeneric · PowertrainReductant Heater B Control Circuit Low
- P20C0Generic · PowertrainReductant Heater B Control Circuit High
- P20C1Generic · PowertrainReductant Heater C Control Circuit/Open
