P0012: Camshaft Timing Over-Retarded (Bank 1)
The P0012 code indicates that the engine control module (ECM) has detected that the camshaft timing on bank 1 is retarded (delayed) beyond the specified range. This typically occurs when the variable valve timing (VVT) system fails to advance the camshaft as commanded, often due to low oil pressure, a faulty VVT solenoid, or a stretched timing chain. Bank 1 refers to the side of the engine containing cylinder 1.
01. Most Common Causes
- Low or dirty engine oil
- Faulty VVT solenoid (oil control valve)
- Stretched or slipped timing chain/belt
- Worn timing chain tensioner or guides
- Faulty camshaft phaser/actuator
- Engine mechanical issues (low oil pressure)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Rough idle or engine misfire
- Reduced engine power and acceleration
- Poor fuel economy
- Engine may stall or hesitate
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Check engine oil level and condition; change if dirty or low.
Step 3: Inspect VVT solenoid and wiring; test solenoid resistance and operation.
Step 4: Perform a mechanical timing check to verify timing chain/belt alignment.
Step 5: Monitor camshaft and crankshaft position sensor data with a scan tool.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can cause poor performance and potential engine damage. Immediate diagnosis is advised.
How much does it cost to fix?▼
Costs vary from $50 for an oil change to $150 for a VVT solenoid replacement. Major repairs like timing chain replacement can cost $500-$1500.