Crankshaft Position - Camshaft Position Correlation (Bank 1 Sensor A)
The crankshaft (turned by the pistons) and the camshafts (which open the valves) turn linked by the timing chain or belt. This code means the sensor A camshaft —usually the intake one— on bank 1 (the cylinder 1 side) is not in the position that matches the crankshaft.
What the car has detected
The engine computer compares the crankshaft and camshaft sensor signals and has seen the cam running advanced or retarded by more degrees than allowed.
The most serious cause is a stretched timing chain or one that has jumped a tooth: if it gets worse, the valves can hit the pistons and wreck the engine. Avoid long trips and get it to a garage as soon as possible.
Symptoms
- Engine warning light on
- Chain noise or rattle, especially on cold start
- Rough idle or hesitation
- Loss of power or limp mode
- Hard starting
Possible causes
- Stretched timing chain (common at high mileage) or one that has jumped a tooth
- Worn timing tensioner or guides
- Stuck camshaft phaser (variable timing) or its control valve
- Low, old or wrong-viscosity oil that doesn't feed the phaser properly
- Faulty camshaft or crankshaft sensor, or a shifted reluctor wheel
- Timing assembled incorrectly after a repair
Checks for the garage
- Ask whether engine or timing work was done recently
- Check the oil level and condition
- Compare requested and actual cam angle in live data
- Look for other timing codes: several at once point to the main chain
- Verify the timing marks per the manual and the condition of chain and tensioners
- Check the phasers and their control valves
Next step
Check the oil level and have the timing (chain or belt, tensioners) and the camshaft phaser checked.
Go to a garage as soon as possible, especially if you can hear the chain. Checking timing and the chain needs specific tools and the engine manual.