Powertrain, generic · Fuel and air metering, auxiliary emission controls
P0012 "A" Camshaft Position - Timing Over-Retarded (Bank 1)
Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible
The engine control module compares the commanded position of the intake camshaft on bank 1 with the actual position from the camshaft and crankshaft sensors. This code is set when the camshaft stays further retarded than commanded for longer than a calibrated time. Usually the phaser does not move far enough out of its rest position, because oil pressure is too low to release the locking pin, the oil control valve does not open, or the oil screen is blocked. A stretched timing chain also shifts the camshaft towards retarded. Bank 1 is the cylinder bank that contains cylinder 1.
Likely causes
Oil pressure or oil level too low, oil worn out
Oil control valve sticking closed or its screen blocked
Cam phaser defective or seized in its rest position
Timing chain stretched or jumped a tooth
Wear debris in the oil circuit, e.g. from a thrust bearing
Symptoms
- Check engine light on
- Noticeably less torque and pulling power
- Higher fuel consumption
- Harder starting in some cases
- Rattle from the timing drive if the chain is stretched
Repair estimate
DifficultyMediumDIY possible
Parts and labour€60–2,500
Time0–10 h
Typical range across vehicles; the real cost depends on what the testing finds.
What to check first
- Check oil level and service history
- Test the timing solenoid operation
- Verify mechanical timing marks
Parts involved
cam phaser intake bank1oil control valve intake bank1engine oiltiming chain
Related codes
References: law.cornell.edu, saabwisonline.com, patents.google.com, en.wikipedia.org.