P0012

What it means

P0012 means the engine control unit has found the 'A' camshaft on Bank 1 is over-retarded, so its timing is later than the commanded position. The ECU compares the camshaft position sensor signal with the crankshaft position signal and the target set for the variable valve timing system. When the difference stays outside the allowed limit for too long, the code is stored and the warning light comes on.

Symptoms

• Engine warning light on
• Rough or unstable idle
• Hesitation or loss of power, especially at low revs
• Poor fuel economy
• Hard starting or extended cranking
• Rattling or ticking noise from the engine at start-up

Possible causes

• Low, dirty or degraded engine oil, or the wrong grade for the engine, which starves or slows the variable valve timing systemlikely
• Faulty or sticking camshaft oil control (phaser) solenoid or its blocked oil screenlikely
• Faulty camshaft phaser (variable valve timing actuator), worn or sticking internallypossible
• Stretched timing chain or worn tensioner or guides, or a belt that has jumped a tooth, giving incorrect mechanical timingpossible
• Wiring or connector fault in the solenoid circuit, such as chafing, corrosion or poor connectionpossible
• Faulty camshaft or crankshaft position sensor, or a damaged reluctor wheel giving a false readingrare
• Engine control unit fault or outdated calibration, where the manufacturer has issued a known update for this faultrare

How to diagnose

1. Read all stored codes and freeze frame data, noting engine temperature, load and revs when the fault set, and check for related camshaft, crankshaft or oil pressure codes
2. Check the engine oil level and condition, and confirm the oil meets the manufacturer's specification and has been changed on time
3. Inspect the solenoid wiring and connector for damage, corrosion, oil contamination and a secure fit
4. Use a scan tool to compare commanded and actual camshaft position at idle and under load, and activate the solenoid if the tool supports it
5. Remove and inspect the oil control solenoid and its filter screen for sludge, debris and sticking, following the procedure for that engine
6. Check the camshaft and crankshaft sensor signals and the reluctor wheels for condition and correct signal pattern
7. Check mechanical timing against the manufacturer's marks and measure timing chain stretch where the engine allows, as the method depends on the model
8. Check for any technical bulletins or calibration updates for the specific engine

How to fix

• Correct the oil level and change the oil and filter using the specified grade, then clear the code and retest
• Replace a faulty or sticking oil control solenoid and clean or replace its screen
• Replace the camshaft phaser if it is worn or not responding
• Replace the timing chain, tensioner and guides, or the belt, and set the timing correctly
• Repair or replace damaged wiring and connectors in the solenoid circuit
• Replace a faulty camshaft or crankshaft sensor, or apply a manufacturer calibration update only if one is known to address this fault

Can I keep driving?

This code for other makes

• P0012AudiCamshaft variable timing solenoid failure, Engine oil level is too low, The engine is not timed correctly, The engine oil does not meet the manufacturer's requirements, Variable valve timing actuator failure, Worn timing chain

Nearby codes

• P0011GenericA Camshaft Position - Timing Over-Advanced or System Performance Bank 1
• P0013GenericB Camshaft Position Actuator A Control Circuit/Open Bank 1