P0018 means Crankshaft Position – Camshaft Position Correlation (Bank 2 Sensor A). The crankshaft signal and the bank 2 sensor A camshaft signal are out of their expected relationship, so camshaft timing on bank 2 does not line up with the crankshaft. It is a generic OBD-II code, so the definition is the same on any make, but the most likely cause varies by engine; confirm with a scan tool and the service information for your vehicle before buying parts.
What P0018 means
The engine computer uses the crankshaft position sensor to know engine speed and piston position, and the camshaft sensors to know which stroke each cylinder is on. On engines with variable valve timing, oil-driven cam phasers rotate the camshafts relative to the crankshaft under the control of solenoids. Timing codes come from a sensor that cannot be read, or from a measured cam angle that does not match the commanded one, so oil level and condition, sensor signals and mechanical timing all need checking.
P0018 symptoms
- Check engine light
- Rattle at cold start
- Rough running or hard starting
Common causes of P0018
- Stretched timing chain or worn guides and tensioner on bank 2
- Cam phaser or solenoid problems on bank 2
- Low oil level or pressure
- Faulty cam or crank sensor
How to diagnose P0018
- Check oil level and condition
- Compare cam and crank correlation values for both banks
- Note any matching bank 1 codes (P0016, P0017), which point to a shared chain or oil problem
- Inspect sensors, then verify mechanical timing
Can you drive with P0018?
Drive gently and repair soon; a badly stretched chain can jump a tooth.
P0018 tips
Some V6 engines, including certain GM 3.6-liter engines, are known for setting several timing codes together (such as P0008, P0016, P0017, P0018 and P0019) when the timing chains stretch. Seeing codes on both banks at once points to the chains rather than one solenoid.
Will P0018 clear itself?
If the fault stops, the computer turns off the check engine light by itself after several drive cycles without seeing it again, and the code stays in memory as history for a while. Clearing P0018 with a scan tool after a repair is fine, but if the cause is still there the code returns, sometimes within one drive. Disconnecting the battery also clears codes on most vehicles, but it erases learned fuel trims and idle settings as well.
Related codes
| Code | Meaning |
|---|---|
| P0019 | Crankshaft Position – Camshaft Position Correlation (Bank 2 Sensor B) |
| P0016 | Crankshaft Position – Camshaft Position Correlation (Bank 1 Sensor A) |
| P0017 | Crankshaft Position – Camshaft Position Correlation (Bank 1 Sensor B) |
| P0345 | Camshaft Position Sensor A Circuit (Bank 2) |
Guides that help
- camshaft position sensor
- VVT solenoid
- timing chain and cam phaser symptoms
- crankshaft and camshaft position sensors
- low oil pressure
When it is more than a sensor
If a stretched chain has already jumped time and damaged valves, or low oil pressure has worn the engine, a repair can cost more than a replacement; see engine replacement cost and compare engines by code on our engines page.
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