P0012 – “A” Camshaft Position – Timing Over-Retarded

The P0012 OBD2 code indicates there’s a problem with your engine’s timing. Most cars on the road today use a variable timing system. This allows them to run more efficiently and get better fuel economy, but it can also lead to serious performance issues when the timing is disrupted.

Engine’s timing problem is showed by the P0012 OBD2 code
The P0012 OBD2 code indicates there’s a problem with your engine’s timing

While the P0012 trouble code is serious, 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 on any vehicle that uses variable camshaft timing (VCT) variable valve timing (VVT). As a generic powertrain code, it can be seen on any vehicle that uses the OBD2 diagnostic system. 

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 improper lubrication of the camshaft, one of the main reasons this trouble code is potentially serious. 

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 VCT system
  • Short in VCT system
  • Failed VCT solenoid
  • 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 vehicle 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:

  1. Scan your vehicle using an OBD2 code reader and make note of any codes that come up, as these can help guide your diagnosis. Clear all codes.  
  2. 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. Oil that is too thick can cause similar system malfunctions and trouble codes to contaminated oil. 
  3. Test drive your vehicle and scan again to see if the P0012 trouble code comes back.
  4. Inspect the wires on the harness for the bank 1 “A” camshaft. Replace any that are frayed or damage, and ensure that all connections are secure. 
  5. 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. 
  6. If you don’t see any sludge in the valve train, locate and inspect the oil control valve. Ensure that it is able to open and shut smoothly. If it is clogged, blocked, or stuck, replace the oil control valve. 
  7. Use an oil pressure gauge to test your engine’s oil pressure. Start by getting your engine to normal 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.
  8. If the code still will 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. Very often, the P0012 trouble code is 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 serious 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. 

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