P0018: Crankshaft Position - Camshaft Position Correlation (Bank 2 Sensor A)
Severity: high
What it means: The crankshaft and bank 2 camshaft (sensor A) signals don't line up the way they should, which suggests a timing relationship problem on the second cylinder bank.
Safe to drive? Have it checked soon. A stretched or jumped timing chain can lead to engine damage.
Common symptoms
- Check-engine light
- Rattle at startup
- Rough running
- Hard start or no-start
Likely causes, ranked
- Stretched timing chain or worn guides/tensionerShop
- Faulty cam or crank position sensorDIY
- Sticking cam phaser or oil control solenoidShop
- Low oil level or pressureShop
Vehicle-specific notes
- 2007–2010 Saturn Outlook: GM's PIP3423N covers P0016–P0019, P0008 and P0009 on its V6s, including timing chain checks. Read the full answer · Source
- 2007–2012 GMC Acadia: 3.6L timing chain stretch; GM special coverage 11340C covered some 2007 and 2009 models (expired). Read the full answer · Source
What it means: The crankshaft and bank 2 camshaft (sensor A) signals don't line up the way they should, which suggests a timing relationship problem on the second cylinder bank.
Severity: High. Safe to drive? Have it checked soon. A stretched or jumped timing chain can lead to engine damage.
DIY or shop?
Sensor and oil checks are DIY. Timing chain work is a shop job.
Before you replace parts
- Check the oil level and condition first.
- Read all stored codes. Cam/crank correlation codes often show up together.
- Have a shop check cam timing deviation with a scan tool before replacing chains.
- Check your VIN for recalls, service bulletins and extended coverage.
Safety / mechanic note
Verify with a mechanic. Stop driving if the engine runs rough or rattles loudly. A code points to a circuit or system, not always a specific part.