Generic fault codes
9415 Generic OBD-II fault codes: what each one means, 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.
- P21A0Generic · PowertrainCylinder 5 Air-Fuel Ratio Imbalance
- P21A1Generic · PowertrainCylinder 6 Air-Fuel Ratio Imbalance
- P21A2Generic · PowertrainCylinder 7 Air-Fuel Ratio Imbalance
- P21A3Generic · PowertrainCylinder 8 Air-Fuel Ratio Imbalance
- P21A4Generic · PowertrainCylinder 9 Air-Fuel Ratio Imbalance
- P21A5Generic · PowertrainCylinder 10 Air-Fuel Ratio Imbalance
- P21A6Generic · PowertrainCylinder 11 Air-Fuel Ratio Imbalance
- P21A7Generic · PowertrainCylinder 12 Air-Fuel Ratio Imbalance
- P21A8Generic · PowertrainReductant Level Sensor B Circuit
- P21A9Generic · PowertrainReductant Level Sensor B Circuit Range/Performance
- P21AAGeneric · PowertrainReductant Level Sensor B Circuit Low
- P21ABGeneric · PowertrainReductant Level Sensor B Circuit High
- P21ACGeneric · PowertrainReductant Level Sensor B Circuit Intermittent/Erratic
- P21ADGeneric · PowertrainReductant Level Sensor C Circuit
- P21AEGeneric · PowertrainReductant Level Sensor C Circuit Range/Performance
- P21AFGeneric · PowertrainReductant Level Sensor C Circuit Low
- P21B0Generic · PowertrainReductant Level Sensor C Circuit High
- P21B1Generic · PowertrainReductant Level Sensor C Circuit Intermittent/Erratic
- P21B2Generic · PowertrainExcessive Time To Enter Closed Loop NOx Adsorber Control
- P21B3Generic · PowertrainClosed Loop NOx Adsorber Control At Limit - Too High
- P21B4Generic · PowertrainNOx Adsorber - Over Temperature Bank 1
- P21B5Generic · PowertrainNOx Adsorber - Over Temperature Bank 2
- P21B6Generic · PowertrainCold Start Cylinder 1 Injection Timing
- P21B7Generic · PowertrainCold Start Cylinder 2 Injection Timing
- P21B8Generic · PowertrainCold Start Cylinder 3 Injection Timing
- P21B9Generic · PowertrainCold Start Cylinder 4 Injection Timing
- P21BAGeneric · PowertrainCold Start Cylinder 5 Injection Timing
- P21BBGeneric · PowertrainCold Start Cylinder 6 Injection Timing
- P21BCGeneric · PowertrainCold Start Cylinder 7 Injection Timing
- P21BDGeneric · PowertrainCold Start Cylinder 8 Injection Timing