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.
- P1137Saturn · PowertrainHO2S Bank 1 Sensor 2 Lean Or Low Voltage
- P1137Subaru · PowertrainFront Oxygen AF Sensor Circuit Range Performance Problem
- P1137Volkswagen · PowertrainLong Term Fuel Trim Add Fuel Bank 1 System Too Rich
- P1138BMW · PowertrainO2 Sensor Heater Circuit Low Voltage Bank 1 Sensor 2
- P1138Buick · PowertrainHO2S Bank 1 Sensor 2 Rich Or High Voltage
- P1138Cadillac · PowertrainHO2S Bank 1 Sensor 2 Rich Or High Voltage
- P1138Chevrolet · PowertrainHO2S Bank 1 Sensor 2 Rich Or High Voltage
- P1138Chrysler · PowertrainHO2S Bank 1 Sensor 2 Rich Or High Voltage
- P1138Ford · PowertrainLack of Downstream Heated Oxygen Sensor Switch Sensor Indicates Rich Bank 1
- P1138GM · PowertrainHO2S Bank 1 Sensor 2 Rich Or High Voltage
- P1138GMC · PowertrainHO2S Bank 1 Sensor 2 Rich Or High Voltage
- P1138Jaguar · PowertrainLack Of HO2S12 Switches Sensor Indicates Rich
- P1138Lincoln · PowertrainLack of Downstream Heated Oxygen Sensor Switch Sensor Indicates Rich Bank 1
- P1138Mazda · PowertrainHO2S Bank 1 Sensor 2 Signal Above 0.45v AF Ratio Too Rich
- P1138Mercury · PowertrainLack of Downstream Heated Oxygen Sensor Switch Sensor Indicates Rich Bank 1
- P1138Oldsmobile · PowertrainHO2S Bank 1 Sensor 2 Rich Or High Voltage
- P1138Other · PowertrainLack Of HO2S12 Switch - Sensor Indicates Rich
- P1138Saturn · PowertrainHO2S Bank 1 Sensor 2 Rich Or High Voltage
- P1138Volkswagen · PowertrainLong Term Fuel Trim Add Fuel Bank 2 System Too Lean
- P1139BMW · PowertrainO2 Sensor Heater Circuit High Voltage Bank 1 Sensor 2
- P1139Buick · PowertrainHO2S Insufficient Switching Bank 1 Sensor 2
- P1139Cadillac · PowertrainHO2S Insufficient Switching Bank 1 Sensor 2
- P1139Chevrolet · PowertrainHO2S Insufficient Switching Bank 1 Sensor 2
- P1139Chrysler · PowertrainHO2S Insufficient Switching Bank 1 Sensor 2
- P1139Ford · PowertrainWater In Fuel Indicator Circuit Malfunction
- P1139GM · PowertrainHO2S Insufficient Switching Bank 1 Sensor 2
- P1139GMC · PowertrainHO2S Insufficient Switching Bank 1 Sensor 2
- P1139Lincoln · PowertrainWater In Fuel Indicator Circuit Malfunction
- P1139Mercury · PowertrainWater In Fuel Indicator Circuit Malfunction
- P1139Oldsmobile · PowertrainHO2S Insufficient Switching Bank 1 Sensor 2
