Variable Camshaft Timing Over Retarded – Bank 1
How does a P0012 code trigger the check engine light? This code will trigger the check engine light under the following condition:
The comprehensive component monitor, referred to as the CCM, monitors the Variable Camshaft Timing (VCT) position for over-retarded cam timing. If the cam timing exceeds a maximum calibrated limit or is stuck in a retarded position, the check engine light will come on and set this trouble code.
Incorrect camshaft timing
VCT solenoid valve stuck open or continuous oil flow to piston chamber
Camshaft advance mechanism binding, or faulty VCT unit
This check engine light code is caused by a mechanical fault of the VCT unit or related components, so there is no need for electrical diagnosis. Possible symptoms may include rough idle, stall or hard start. Refer to manufacturer specific component tests for the VCT unit. You may also use the “Get Help” link if you need specifications or have any other related questions. Remember to refer to an appropriate manual for specific instructions.