P0340: Camshaft Position Sensor Circuit
P0340 means the car computer is not getting a correct signal from the camshaft position sensor — which it needs to set ignition timing and fuel injection.
Symptoms
Hard starting or no-start, sudden stalling, hesitation/weakness, sometimes stumbling, with a check engine light.
Common causes
A failed camshaft sensor, cut/corroded wiring or connector, sometimes a timing chain/belt issue or a damaged reluctor ring.
The fix
Check the sensor connector and wiring first, then the sensor itself. If accompanied by intermittent hard starting, the sensor is a strong candidate. OBD2 confirms the lost signal.
FAQ
Difference from the crank sensor?
The crankshaft sensor is essential for starting and its failure often prevents starting entirely; the camshaft sensor is for precise timing and may allow a difficult start.
Can I drive with P0340?
The engine may stall suddenly — delaying is not advised; inspect it soon.