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.
- P1818Saturn · PowertrainTFP Valve Position Switch Drive Without Drive Ratio
- P1818Volkswagen · PowertrainPressure Control Solenoid 2 Electrical
- P1819Buick · PowertrainInternal Mode Swtich No Start, Wrong Range
- P1819Cadillac · PowertrainInternal Mode Switch No Start Wrong Range
- P1819Chevrolet · PowertrainInternal Mode Switch No Start Wrong Range
- P1819Ford · PowertrainTransmission Neutral Safety Switch Short Circuit To Ground
- P1819GM · PowertrainInternal Mode Switch No Start Wrong Range
- P1819GMC · PowertrainInternal Mode Switch No Start Wrong Range
- P1819Lincoln · PowertrainTransmission Neutral Safety Switch Short Circuit To Ground
- P1819Mercury · PowertrainTransmission Neutral Safety Switch Short Circuit To Ground
- P1819Oldsmobile · PowertrainInternal Mode Switch No Start Wrong Range
- P1819Other · PowertrainTransmission Neutral Safety Switch Short Circuit To Ground
- P1819Saturn · PowertrainInternal Mode Swtich No Start Wrong Range
- P1819Volkswagen · PowertrainPressure Control Solenoid 2 Open Short To Ground
- P1820Buick · PowertrainInternal Mode Switch Circuit A Low
- P1820Cadillac · PowertrainInternal Mode Switch Circuit A Low
- P1820Chevrolet · PowertrainInternal Mode Switch Circuit A Low
- P1820Ford · PowertrainTransmission Transfer Case Clockwise Shift Relay Coil Circuit Failure
- P1820GM · PowertrainInternal Mode Switch Circuit A Low
- P1820GMC · PowertrainInternal Mode Switch Circuit A Low
- P1820Lincoln · PowertrainTransmission Transfer Case Clockwise Shift Relay Coil Circuit Failure
- P1820Mercury · PowertrainTransmission Transfer Case Clockwise Shift Relay Coil Circuit Failure
- P1820Oldsmobile · PowertrainInternal Mode Switch Circuit A Low
- P1820Other · PowertrainTransmission Transfer Case Clockwise Shift Relay Coil Circuit Failure
- P1820Saturn · PowertrainInternal Mode Switch Circuit A Low
- P1820Volkswagen · PowertrainPressure Control Solenoid 2 Short To B+
- P1821Other · PowertrainTransmission Transfer Case Clockwise Shift Relay Coil Open Circuit
- P1822Buick · PowertrainInternal Mode Switch Circuit B High
- P1822Cadillac · PowertrainInternal Mode Switch Circuit B High
- P1822Chevrolet · PowertrainInternal Mode Switch Circuit B High
