P0012 is an OBD-II generic trouble code that indicates a vehicle’s ECM (engine control module) has detected the intake camshaft timing on Bank 1 (number 1 cylinder side of the engine) does not correspond with the intake camshaft timing (in degrees).
In this case, the ECM has found the camshaft timing is over-retarded; meaning that the intake camshaft opens too long after the engine’s intake cycle. Proper diagnosis will be required to find the reason for the P0012 trouble code.
It is possible your vehicle is experiencing noticeable drivability problems and/or idle and starting issues because of this fault code.
What are the Causes of the P0012 Code?
Engine valve timing is variable (on most gasoline and diesel-powered vehicles on the road today), hence the term “Variable Valve Timing”.
What does this mean? The engine control module is able to adjust when the spark plugs are fired, and at which precise moment the intake and exhaust valves open and close.
The timing of these events very much affects the efficiency of combustion. In some engine designs, the intake and exhaust camshaft timing is regulated solely by electronic components. On most others, the system is controlled by hydraulics and with the use of electronic valves to control oil flow/pressure.
For those engines using a hydraulic system, it is important to ensure the engine oil is of the required viscosity, not contaminated, and of the required amount/level; as recommended by the vehicle’s manufacturer.
Causes of the P0012 Code
Here are a few things that could cause the ECM to trigger a P0012 fault:
- Engine oil is too low
- Dirty/sludge engine oil
- Low oil pressure
- Malfunctioning camshaft timing
- Short in intake timing control/oil control circuit
- Faulty intake valve timing control solenoid
- Faulty oil control valve (OCV)
Symptoms of P0012 Code
- The ECM will turn on the Check Engine Light.
- 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 the 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 to Diagnose the P0012 Code
The diagnosis of this fault should begin with ensuring the engine oil and oil filter are within their respective effective use lifetime. Triggering a P0012 trouble code due to old oil is rare but certainly possible. Since this inspection is the simplest to do, check your engine oil first.
Next, we’d recommend clearing the P0012 trouble code from the ECM memory using a scan tool, and watching to see if the check engine illuminates again (clearing the P0012 will extinguish the CEL/MIL light).
If the light turns back on immediately after you’ve cleared the code and restarted the engine, you can be confident there is a mechanical fault that needs to be repaired without waiting. If it doesn’t, then perhaps the fault was intermittent and caused by an unexpected irregular engine operating condition.
Continue to drive your vehicle for at least 100 miles and over the course of a few days in order to make the “Emission Monitors” ready for the smog check as well as to ensure the check engine light does not illuminate.
If the check engine light returns and a trouble code P0012 is once again stored in the ECM.
We recommend getting a diagnosis from a reputable smog repair station.
Diagnosing a P0012 trouble code requires specialized tools and specific knowledge of engine emissions; which would be tough to go into the entire detail, as it requires extensive repair and diagnosis knowledge and misdiagnosis will most certainly result in monies spent unnecessarily, or worse, greater engine damage.
Clear the trouble code from ECM and check to see if the check engine light or MIL turns on again.
Examine engine oil for proper viscosity and level. Check/replace the oil filter is passed its operational lifetime.
Inspect/replace bank 1 intake valve camshaft oil control valve. Check/replace bank 1 intake camshaft oil control valve solenoid.
Correct timing chain position (Jumped camshaft timing chain/sprocket/skipped gear tooth).
How Much does it Cost to Fix the P0012 Code?
The amount will depend on the severity or source of the problem. In some cases, the P0012 code is only caused by frayed or loose wiring.
The mechanic will need to check all electrical connections in the camshaft sensor, oil control solenoid valve, and crank sensor. This also involves breaking the wiring harness to visually inspect all related wiring.
In the absence of wiring or electrical problems, the problem can also be fixed by a basic oil change. Remember to change the oil filter and use the recommended engine oil to avoid any problems in the future.
If this is the case, you’ll only need to spend around $50. Replacing the valve control solenoid will cost more money. If this is the case, prepare to spend anywhere from $150 to $300 on parts and labor.
The cost might also include replacing the timing belt and tensioner.
Repairs that can fix the P0012 Code
A few different repairs 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 them as needed.
Your engine may run erratically and stall, hesitate, run rough or have a hard starting condition when you have a P0012 situation.
The vehicle may also consume fuel excessively. You might experience carbon fouling of engine components, and various drive complaints depending on the camshaft’s failed position.
Driving the vehicle for a prolonged time while the camshafts are retarded may cause other problems to the valve train or engine depending on the cause of the failure. So we advise immediate fix.