Fuel & air metering · Powertrain · generic (SAE-defined)

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

P0012 means the Bank 1 "A" camshaft (usually intake) is sitting later, or more retarded, than the engine computer commanded.

Severity: Moderate — diagnose within days
Can I drive with P0012? Generally yes for short distances, though the engine may idle poorly or feel weak. Top off or change the oil first, and do not put off the diagnosis, since a worn phaser or stretched chain can lead to more serious timing problems.

Standard title per SAE J2012 / ISO 15031-6 · Updated 2026-11-07 · By CarWhere Research

How P0012 sets

The powertrain control module (PCM) uses the camshaft and crankshaft position sensors to measure how far the Bank 1 "A" camshaft has moved relative to the crankshaft. When it commands retard or holds the cam at a target, and the measured position stays retarded beyond the allowed error, P0012 sets. Many engines also check this right after startup, when the phaser should return to its base lock position. Thresholds vary by manufacturer.

Common causes of P0012

Roughly most likely first; the actual cause depends on the vehicle and needs testing to confirm.

  1. Low oil level, sludge or wrong oil viscosity
  2. VVT oil control solenoid stuck in the retard position
  3. Cam phaser not locking at its home position
  4. Stretched timing chain or worn tensioner
  5. Restricted oil passage or clogged solenoid screen
  6. Cam timing set incorrectly during a repair

P0012 symptoms

  • Check engine light on
  • Hard starting or rough idle
  • Lack of low-end power
  • Lower fuel economy
  • Brief rattle at cold start on some engines

How P0012 is diagnosed

  1. Verify oil level, condition and viscosity before anything else
  2. Record freeze frame and check for P0011, P0016 or solenoid circuit codes
  3. Watch desired versus actual Bank 1 cam angle in live data
  4. Command the solenoid and check that the cam angle responds smoothly
  5. Pull the solenoid and inspect it and its oil screen for debris
  6. Check timing chain stretch and phaser lock function if the solenoid tests good

Typical fixes for P0012

  • Change oil and filter using the specified grade
  • Replace the Bank 1 "A" oil control solenoid
  • Replace the intake cam phaser
  • Replace the timing chain set if stretch is confirmed
  • Re-time the engine if timing marks are out of alignment

Replace parts only after testing confirms the cause — a code names the circuit or condition that failed a check, not necessarily the faulty part. We don’t publish per-repair prices; for what households actually spend on upkeep, see car repair costs.

Manufacturer notes

Commonly reported on Toyota, Hyundai/Kia and GM engines with oil-pressure-actuated cam phasers. Camshaft "A" is intake on most makes, but definitions can vary by manufacturer; check factory service information.

Related codes & warning lights

P0010P0011P0016P0022P0014

P0012 FAQ

What does code P0012 mean?

P0012 means the Bank 1 "A" camshaft (usually intake) is sitting later, or more retarded, than the engine computer commanded. The standard definition is ""A" Camshaft Position - Timing Over-Retarded (Bank 1)."

Can I drive with a P0012 code?

Generally yes for short distances, though the engine may idle poorly or feel weak. Top off or change the oil first, and do not put off the diagnosis, since a worn phaser or stretched chain can lead to more serious timing problems.

Can a bad camshaft sensor cause P0012?

It can, because the PCM relies on that sensor to measure cam angle, but sensor faults usually set their own circuit codes. The solenoid, oil supply and phaser are more common culprits.

Why does P0012 often appear after a timing belt or chain job?

If the cam is installed one tooth off, the PCM sees a retarded cam angle it cannot correct, which sets P0012 or a correlation code.

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Sources

General information written by CarWhere Research, not a diagnosis of your vehicle. Manufacturers can add their own sub-definitions and test conditions; confirm with the factory service information for your year, make and model. Before paying for a repair, check NHTSA for open recalls and your warranty booklet: federal law requires an emissions warranty on major emission-control parts such as the catalytic converter and engine computer.