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.
- U0001Audi · NetworkA faulty wheel speed sensor, A problem with the wheel speed sensor circuit, Reluctor issues, A problem with the ABS module
- U0073Audi · NetworkA faulty control module, A problem with the CAN bus
- U0100Audi · NetworkA faulty PCM, A problem with the control module circuit, A problem with the CAN bus
- U0107Audi · NetworkA dead battery, A faulty TAC module, A problem with TAC module circuit, A problem with the CAN bus
- U0121Audi · NetworkA dead battery, A faulty ABS module, A problem with ABS module circuit, A problem with the CAN bus