Engine

P0012 — Intake camshaft timing over-retarded (Bank 1)

Severity: medium Drive with care, to a shop

What P0012 means

The ECM compares the commanded and actual intake camshaft angle on Bank 1 using the camshaft and crankshaft position sensors. The cam phaser is normally moved by oil pressure, controlled by an oil control (VVT) solenoid. P0012 sets when the camshaft stays too far retarded versus the target.

Symptoms

  • Check engine light on
  • Rough idle
  • Reduced power and sluggish acceleration
  • Hard starting or stalling
  • Worse fuel economy
  • Chain rattle on startup

Possible causes

  1. Stuck or faulty VVT oil control solenoid
  2. Low, dirty or wrong-viscosity engine oil
  3. Stretched timing chain or worn tensioner or guides
  4. Clogged solenoid screen or low oil pressure
  5. Failed VVT cam phaser
  6. Faulty camshaft position sensor
  7. Damaged wiring or poor connection in the VVT solenoid or sensor circuit

How to diagnose

  1. Read codes and freeze frame data, and look for other cam or misfire codes
  2. Check oil level and condition, and change oil and filter with the correct grade if needed
  3. Inspect the connector and wiring of the VVT solenoid and cam sensor
  4. Compare commanded and actual cam angle in live data
  5. Command the VVT solenoid with a scan tool and watch for a change in cam angle and idle
  6. Remove the solenoid, inspect its screen for debris and test coil resistance
  7. Measure oil pressure with a mechanical gauge
  8. Assess timing chain stretch via cam/crank correlation data or by checking timing marks

Common fixes

  • Oil and filter change with the specified oil
  • Clean or replace the VVT oil control solenoid
  • Replace the camshaft position sensor
  • Repair wiring and connectors
  • Replace the timing chain or belt, tensioners and guides
  • Replace the VVT phaser

P0012 on different brands

Ford · manuals
On Ford, P0012:00 means the engine monitor detected Bank 1 intake camshaft timing over-retarded; it describes the monitored condition, not a confirmed failed part.

Questions and answers

Can I drive with P0012?

Only briefly and gently, for example to a repair shop. If oil pressure or the timing chain is the cause, continued driving can badly damage the engine.

Can bad oil cause P0012?

Yes, it is one of the most common causes. VVT runs on oil pressure, so low, dirty or wrong-viscosity oil upsets cam timing.

What should I check first for P0012?

Check the oil level and condition and change it if needed. Then clear the code and see if it returns; if it does, test the VVT solenoid and timing chain.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.