OBD-II · Engine and powertrain (P)
P0012
A camshaft position timing over-retarded bank 1
What it means
The A camshaft on bank 1 (usually intake) is not at the position the ECU commands; it is too far retarded.
Symptoms
- engine warning light
- rough idle, especially when warm
- reduced power or poor pulling at low revs
- rattle at cold start if the timing chain or adjuster is worn
Likely causes, most likely first
| No. | Cause |
|---|---|
| 01 | low oil level or wrong oil grade |
| 02 | sticking or sludged camshaft adjuster solenoid (oil control valve) or its filter screen |
| 03 | stretched timing chain or worn tensioner/guides |
| 04 | faulty camshaft adjuster (phaser) |
| 05 | timing set incorrectly after belt or chain work |
| 06 | camshaft position sensor fault |
What to check, step by step
- 01Check the oil level and that the oil meets the maker's specification
- 02Read the actual versus target camshaft angle and the cam/crank deviation values in live data
- 03Remove, inspect and clean or replace the camshaft adjuster solenoid and its filter screen
- 04Listen for timing chain rattle at cold start
- 05Check the mechanical timing and chain stretch (workshop job)