The P0012 OBD2 code indicates there’s a problem with your engine’s timing. Today, most cars on the road use a variable timing system that allows them to run more efficiently and get better fuel economy. However, it can also lead to serious performance issues when the timing is disrupted.
While the P0012 trouble code is severe, it can also be very quick and affordable to fix. In many cases, a simple oil change is all you need. The important thing is to address it right away before more costly issues have a chance to develop.
P0012 Code Definition:
P0012 (Generic): “A” Camshaft Position – Timing Over-Retarded (Bank 1)
What Does P0012 Mean?
The P0012 diagnostic code can trigger in any vehicle that uses variable camshaft timing (VCT) variable valve timing (VVT), especially cars that use the OBD2 diagnostic system as a generic powertrain code.
Variable timing in your engine allows it to be more efficient, adapting the amount of power produced to the engine’s needs. The engine control module (ECM) or powertrain control module (PCM) determines the correct position of all engine components at a given time.
The position of the camshaft is adjusted using oil control valves (OCV). Also called VCT solenoids, these valves allow more or less oil into the camshaft according to the engine’s needs. Malfunctions of the VCT solenoids can lead to the camshaft’s improper lubrication, one of the main reasons this trouble code is potentially severe.
The ECM or PCM monitors all the components of your engine, as well, to make sure they’re in the correct positions. If the camshaft is determined to be behind its anticipated position, the P0012 trouble code is triggered.
This code points you specifically to the Bank 1 “A” camshaft. Bank 1 is the side of your engine that contains the first cylinder. Depending on your vehicle, the “A” camshaft can be the left, front, or intake camshaft. Check your manual if you need help identifying it in your engine.
The P0012 code can trigger during either the advancing or the retarding phases of the camshaft’s positioning. While this is a camshaft code, it more often indicates a problem with the oil or the valves than with the camshaft itself.
What Are The Symptoms Of The P0012 Code?
The drivability symptoms associated with P0012 vary depending on the position of the camshaft when the problem occurs. Common symptoms include:
- Activation of the check engine light
- Engine running rough
- Stalls or hard starts
- Knocking and rattling in the engine
- Engine misfires
- Reduced fuel economy
What Are The Causes Of P0012?
The most common causes of the P0012 trouble code are:
- Too little oil in the engine
- Oil is old or dirty
- Oil control valve stuck open
Other causes of P0012 include:
- Loose or damaged wires in the VCT system
- Short in the VCT system
- Failed VCT solenoid
- The stuck or damaged camshaft phaser
- Engine sludge impeding flow of oil to VCT piston
- Oil pressure too low
How Serious Is The P0012 Code?
The P0012 trouble code is of high severity. The drivability issues associated with this DTC could cause long-term damage to your engine and potentially make your vehicle unsafe to drive. You should stop driving your car and take it for immediate repairs if P0012 triggers, especially if it appears in conjunction with misfire trouble codes.
How To Diagnose And Fix The P0012 Code
Tools you’ll need:
- OBD2 scan tool
- Engine oil pressure gauge
- Basic hand tools
- Scan your vehicle using an OBD2 code reader and make a note of any codes that come up, as these can help guide your diagnosis. Clear all codes.
- Check the level and condition of your oil. If the level is low, refill to the level specified in your manual. If it’s dirty, change both the oil and the oil filter. Also, verify that you are using the correct oil viscosity for your engine. The oil that is too thick can cause similar system malfunctions and trouble codes to contaminated oil.
- Test drive your vehicle and scan again to see if the P0012 trouble code comes back.
- Inspect the wires on the harness for the bank 1 “A” camshaft. Replace any that are frayed or damaged, and ensure that all connections are secure.
- Visually inspect the valve train for sludge. Engine sludge can block passages, preventing oil from flowing correctly. If there is sludge, an engine flush may correct your problem. Consult your mechanic for advice on how to proceed.
- If you don’t see any sludge in the valve train, locate and inspect the oil control valve. Ensure that it can open and shut smoothly. If it is clogged, blocked, or stuck, replace the oil control valve.
- Use an oil pressure gauge to test your engine’s oil pressure. Start by getting your engine to average operating temperature, and run the test when the P0012 code is active. If the oil pressure is too low, the problem is likely with the oil pump or oil pressure regulator.
- If the code still does not clear, the engine’s timing could have jumped and need to be reset. Take your vehicle to a mechanic for further diagnosis.
Common Mistakes To Avoid While Diagnosing The P0012 Code
Verify there is a problem with your engine components before you start on any repairs. The P0012 trouble code is often caused by maintenance problems, like engine sludge and low oil. Address these problems first, then use both visual and mechanical tests to verify the source of further problems. This will prevent you from making unnecessary (and potentially costly) repairs.
Tips To Avoid P0012 In The Future
Keeping up with your regular maintenance schedule is the best way to avoid severe engine codes like P0012. Have your oil level, and quality checked according to the maintenance schedule dictated in your manual, and replace or refill it as necessary.