P0340 — Camshaft Position Sensor "A" Circuit
Drive with caution — fix soon.
What P0340 means
P0340 indicates a problem with the camshaft position sensor circuit. This sensor helps the computer track valve timing and coordinate fuel injection and spark. Causes are usually a failed sensor, wiring or connector issues, and it can lead to starting and drivability problems.
Common symptoms
- Check engine light is on
- Hard starting or no-start
- Engine stalling or rough idle
- Hesitation or surging while driving
- Reduced fuel economy
Common causes
- Failed camshaft position sensor
- Damaged or chafed sensor wiring
- Corroded or loose connector
- Faulty timing components affecting the signal
- Oil contamination on the sensor
Typical repair cost
$150 – $550
Varies by vehicle and root cause.
Frequently asked questions
Can I drive with a P0340 code?
Sometimes, but it's a gamble. A failing cam sensor can cause stalling or a no-start without warning, so get it checked promptly.
How much does fixing P0340 cost?
Typically $150 to $550, depending on the sensor's location and how much labor is needed to reach it.
Is P0340 serious?
It's moderate. The car may run, but the risk of stalling or hard starts means you shouldn't leave it unrepaired for long.
What's the difference between the cam and crank sensors?
The crankshaft sensor tracks the crank's rotation, while the camshaft sensor tracks valve timing; the computer uses both to time the engine correctly.