Dirty or contaminated engine oil causing the VVT solenoid to stick or respond slowly; Faulty VVT solenoid (oil control valve) that is clogged, electrically open, or mechanically stuck; Restricted oil passage or sludge buildup in the VVT oil galleries; Worn or stretched timing chain causing the camshaft to be retarded mechanically; Failed camshaft position sensor or damaged wiring to the sensor; Low engine oil level or incorrect oil viscosity preventing proper VVT operation; PCM software issue or faulty PCM (rare, but possible after other causes are ruled out)

DTC codes / P00xx · Fuel and air metering and auxiliary emission controls / P0012

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

Q: What does code P0012 mean?

'A' Camshaft Position - Timing Over-Retarded (Bank 1). P0012 means the engine computer has detected that the bank 1 camshaft is retarded beyond the commanded timing for an extended period. The powertrain control module (PCM) monitors the camshaft position sensor and the variable valve timing (VVT) solenoid, and it sets this code when the actual cam angle stays more retarded than the target angle despite the PCM's commands to advance it.

P0012 means the engine computer has detected that the bank 1 camshaft is retarded beyond the commanded timing for an extended period. The powertrain control module (PCM) monitors the camshaft position sensor and the variable valve timing (VVT) solenoid, and it sets this code when the actual cam angle stays more retarded than the target angle despite the PCM's commands to advance it.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering and auxiliary emission controls

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Rough idle or engine stumble, especially when cold
Reduced engine power or sluggish acceleration
Poor fuel economy compared to normal
Occasional engine misfire or hesitation during acceleration
In some cases, a rattling or ticking noise from the timing chain area

Common causes, most likely first

Dirty or contaminated engine oil causing the VVT solenoid to stick or respond slowly
Faulty VVT solenoid (oil control valve) that is clogged, electrically open, or mechanically stuck
Restricted oil passage or sludge buildup in the VVT oil galleries
Worn or stretched timing chain causing the camshaft to be retarded mechanically
Failed camshaft position sensor or damaged wiring to the sensor
Low engine oil level or incorrect oil viscosity preventing proper VVT operation
PCM software issue or faulty PCM (rare, but possible after other causes are ruled out)

How to diagnose and fix it

Check the engine oil level and condition; top off or change oil and filter if dirty or low
Inspect the VVT solenoid for sludge or debris; clean or replace if contaminated
Test the VVT solenoid electrical resistance and verify it receives power and ground from the PCM
Check the camshaft position sensor signal and wiring for damage or corrosion
Verify oil pressure to the VVT system with a mechanical gauge; repair any oil pump or gallery restrictions
Inspect the timing chain, tensioner, and camshaft phaser for wear or misalignment; replace components as needed
Clear the code and perform a road test to confirm the repair, rechecking live camshaft timing data

Why P0012 Often Isn't the Solenoid

A stretched timing chain can retard the camshaft mechanically, so replacing the VVT solenoid alone will not fix the code if the chain is worn.
Sludge from infrequent oil changes frequently clogs the VVT solenoid screen and oil passages, mimicking an electrical failure.
The code can set intermittently due to low oil pressure at idle, so checking oil pressure when hot is a critical step.
Some vehicles use a camshaft phaser that can fail internally, causing over-retarded timing without any solenoid fault.
A faulty camshaft position sensor or its wiring can send a false retarded signal to the PCM, so always verify the sensor signal before condemning the VVT system.

Can I keep driving with P0012?

You can usually drive the vehicle short distances to a repair shop, but avoid aggressive acceleration or heavy loads because retarded cam timing can cause poor performance and may lead to engine damage over time. If the engine runs very rough or stalls, stop driving and have it towed.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.