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.
- P2518Generic · PowertrainA/C Refrigerant Pressure Sensor B Circuit High
- P2519Generic · PowertrainA/C Request A Circuit
- P251AGeneric · PowertrainPTO Enable Switch Circuit/Open
- P251BGeneric · PowertrainPTO Enable Switch Circuit Low
- P251CGeneric · PowertrainPTO Enable Switch Circuit High
- P251DGeneric · PowertrainPTO Engine Shutdown Circuit/Open
- P251EGeneric · PowertrainPTO Engine Shutdown Circuit Low
- P251FGeneric · PowertrainPTO Engine Shutdown Circuit High
- P2520Generic · PowertrainA/C Request A Circuit Low
- P2521Generic · PowertrainA/C Request A Circuit High
- P2522Generic · PowertrainA/C Request B Circuit
- P2523Generic · PowertrainA/C Request B Circuit Low
- P2524Generic · PowertrainA/C Request B Circuit High
- P2525Generic · PowertrainVacuum Reservoir Pressure Sensor Circuit
- P2526Generic · PowertrainVacuum Reservoir Pressure Sensor Circuit Range/Performance
- P2527Generic · PowertrainVacuum Reservoir Pressure Sensor Circuit Low
- P2528Generic · PowertrainVacuum Reservoir Pressure Sensor Circuit High
- P2529Generic · PowertrainVacuum Reservoir Pressure Sensor Circuit Intermittent
- P252AGeneric · PowertrainEngine Oil Quality Sensor Circuit
- P252BGeneric · PowertrainEngine Oil Quality Sensor Circuit Range/Performance
- P252CGeneric · PowertrainEngine Oil Quality Sensor Circuit Low
- P252DGeneric · PowertrainEngine Oil Quality Sensor Circuit High
- P252EGeneric · PowertrainEngine Oil Quality Sensor Circuit Intermittent/Erratic
- P252FGeneric · PowertrainEngine Oil Level Too High
- P2530Generic · PowertrainIgnition Switch Run Position Circuit
- P2531Generic · PowertrainIgnition Switch Run Position Circuit Low
- P2532Generic · PowertrainIgnition Switch Run Position Circuit High
- P2533Generic · PowertrainIgnition Switch On/Start Position Circuit
- P2534Generic · PowertrainIgnition Switch On/Start Position Circuit Low
- P2535Generic · PowertrainIgnition Switch On/Start Position Circuit High
