P0012 code definition
Camshaft Position “A” - Timing Over-Retarded (Bank 1)
What the P0012 code means
P0012 is the OBD-II generic code indicating the engine control module (ECM) has determined that the intake camshaft timing for bank 1 is more retarded than what the ECM has commanded it be. This over-retarded timing condition could be during the advancing or retarding phase of the camshaft timing.
What causes the P0012 code?
- The variable camshaft timing (VCT) oil control valve (OCV) stuck in the open position.
- The camshaft phaser is damaged and stuck in the retarded position.
- Oil flow problems to the VCT piston and phaser.
What are the symptoms of the P0012 code?
The ECM will turn on the Check Engine Light if the timing cannot be commanded to move.
The engine will have a hard start condition due to the retarded timing position.
Fuel mileage may go down since the camshaft is not in a position to get the best possible fuel mileage.
Depending on camshaft position the engine may stall, hesitate, and run rougher than normal.
The vehicle will fail an emissions test.
Note: Your drive problems will change depending on the camshaft timing positions when the camshaft stopped advancing.
How does a mechanic diagnose the P0012 code?
Visually checks the electrical connections to the camshaft sensor, oil control solenoid valve, and crankshaft sensor for loose connections, damaged wiring harness, or any other issues that may cause a problem.
Makes sure the engine oil is full of clean correct viscosity oil.
The technician will scan and document the codes received and view the freeze frame data to see when the code was set.
The codes should then be reset to clear the OBD-II fault codes and retest the vehicle to see if the P0012 code comes back.
Commands the oil control solenoid valve on and off to see if the camshaft timing changes.
If no problems are noted and the code still exists, then the next step for the technician is to perform a manufacturer's specific pinpoint tests for the P0012 code and repair as needed.
Note: Follow the manufacturer's recommended pinpoint test to narrow down the problem, since each engine may be tested differently and possible engine internal damage may be done if tests are not performed in accordance with a correct procedure.
Common mistakes when diagnosing the P0012 code?
Follow these simple guidelines to prevent mistakes:
Always verify the failure before attempting any repairs.
Do a thorough visual check for any problems with the wiring or connections to the components.
Follow the pinpoint test step-by-step to help prevent a misdiagnosis.
Do not replace any parts unless directed by the pinpoint or visual testing.
How serious is the P0012 code?
The engine may run erratic and stall, hesitate, run rough or have a hard starting condition.
The engine may have excessive fuel consumption, carbon fouling of engine components, and various drive complaints depending on the camshaft failed position.
Driving the vehicle for a prolonged time with the camshafts not retarding may cause other problems to the valve train or engine depending on the cause of the failure.
What repairs can fix the P0012 code?
Resetting the fault codes and performing a road test.
Changing the oil and filter to the proper oil viscosity for the engine's specifications.
Repairing or replacing the wiring or connection to the camshaft oil control solenoid.
Replacing the camshaft oil control valve for bank 1 intake camshaft.
Check the timing chain alignment for jumped timing problems and repair as needed.
Additional comments for consideration regarding the P0012 code
The camshaft phaser controls the timing advance and retard function through oil pressure and oil. The oil needs to be the proper viscosity for the camshaft timing control to work as designed. If you use too thick of oil it can cause this system to malfunction and cause codes and running issues with the engine. Incorrect oil can cause this code and may cause multiple codes along with it.
Need help with a P0012 code?
YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.
This article originally appeared on YourMechanic.com as P0012 OBD-II Trouble Code: Camshaft Position A - Timing Over-Retarded (Bank 1) and was authored by Jay Safford.