P0012 - "A" Camshaft Position - Timing Over-Retarded (Bank 1)
OBD-II DTC Trouble Code Description
"A" Camshaft Position - Timing Over-Retarded (Bank 1)
What does that mean?
A code P0012 refers to the VVT (variable valve timing) or VCT (variable camshaft timing) components and the car's PCM (powertrain control module, also called an ECM). That consists of a few different components but the P0012 DTC specifically refers to the camshaft (cam) timing. In this case, if the cam timing is over-retarded, the engine light will be illluminated and the code will be set. The "A" camshaft is either the intake, left, or front camshaft.
Most likely a P0012 DTC will result in one of the following:
poor idle and/or
There are potentially other symptoms as well. Of course, when trouble codes are set, the MIL (malfunction indicator lamp, a.k.a. the check engine light) illuminates.
A P0012 DTC trouble code may be caused by one or more of the following:
Incorrect camshaft timing
Wiring problems (harness/wiring) in intake timing control valve control solenoid system
Continuous oil flow to VCT piston chamber
Failed timing valve control solenoid (stuck open)
The main thing to check is to verify the operation of the VCT solenoid. You're looking for a sticking or stuck VCt solenoid valve caused by contamination. Refer to vehicle specific repair manual to perform component tests for the VCT unit. Notes: Dealer techs have advanced tools and the ability to follow detailed troubleshooting steps, including the ability to test components using a scan tool.