P0012 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.

Causes

There are several different issues that can cause this trouble code to occur on your OBD II scanner. This could be due to the fact that the variable camshaft timing (VCT) oil control valve (OCV) is stuck in the open position. This error can also be caused because the camshaft phaser is damaged and stuck in the retarded position. This may also be caused by oil flow problems to the VCT piston and phaser.

Symptoms

There are several symptoms that you may notice that may lead you to believe that you have trouble code P0012. This may mean that the variable camshaft timing (VCT) oil control valve (OCV) is stuck in the open position. Once again, the camshaft phaser is damaged and stuck in the retarded position. This can also cause oil flow problems to the VCT piston and phaser.

Diagnosis

There are some methodical steps that mechanics should work through when properly diagnosing trouble code P0012: 

• Visually check the electrical connections to the camshaft sensor, oil control solenoid valve, and crankshaft sensor for loose connections, damaged wiring harness, or any other issues with the connections or wiring that may cause a problem. 
• Make sure the engine oil is full of clean oil, of the correct viscosity. 
• The technician should 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.
• Command 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.

Common mistakes

If you follow the steps listed above, there is a low likelihood that you will face a problem when attempting to diagnose a P0012 trouble code. However, these are some of the most common mistakes that you can face when properly diagnosing this trouble code: 

• 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 this?

There are some issues that trouble code P0012 can cause with a vehicle. The engine may run erratic and stall, hesitate, run rough or have a hard starting condition. The engine may consume fuel excessively, experience carbon fouling of engine components, and various drive complaints depending on the camshaft failed position. Driving the vehicle for a prolonged time while the camshafts are not retarding properly may cause other problems to the valve train or engine depending on the cause of the failure.

What repairs can fix the code?

There are a few different repairs that will fix this problem: 

• Resetting the fault codes and then 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

Related codes

None listed.

Conclusion

If you take these steps and precautions when handling this trouble code, you should have no trouble diagnosing or repairing it. Use this as a step-by-step guide when addressing trouble code P0012.