P0012 – A Camshaft Position – Timing Over-Retarded (Bank 1)

What does P0012 mean?

The Bank 1 intake camshaft timing is more retarded than the computer commanded, and the variable valve timing system cannot correct it. This is the opposite condition to P0011, where timing is over-advanced.

What causes P0012?

Listed from most to least common:

1. 1Low or dirty engine oil (most common root cause)
2. 2Clogged VVT oil control valve screen
3. 3Failed camshaft phaser
4. 4Stuck oil control valve
5. 5Stretched timing chain
6. 6Wiring fault at the oil control valve

Code breakdown

Common symptoms

• Check engine light on
• Rough idle
• Loss of power, particularly at low RPM
• Increased fuel consumption
• Possible rattle from the timing area

How to diagnose

1. 1Check oil level and condition first — overdue or sludgy oil is the leading cause.
2. 2Remove and clean the VVT oil control valve and its filter screen.
3. 3Test the oil control valve electrically and check its resistance.
4. 4Verify oil pressure meets specification.
5. 5If oil and valve are good, investigate the phaser and timing chain.

Usually drivable, but it indicates an oil or VVT problem that tends to worsen if ignored.

Common fixes and estimated costs

Costs are rough US estimates including parts and labor. Actual pricing varies significantly by vehicle, region, and shop rates.

Good to know

Always start with an oil change using the exact viscosity your manufacturer specifies. VVT systems are engineered around specific oil characteristics, and using the wrong weight can itself trigger these codes.

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