Fault codes › Powertrain › Generic (SAE standard) › Ignition system or misfire
P0340 Camshaft position sensor circuit
Needs attention Have it looked at soon. The car is usually driveable with care in the meantime.
What does P0340 mean?
P0340 is a generic powertrain code, defined by the SAE standard, so it means the same thing on every make and model: camshaft position sensor circuit. It belongs to the ignition system or misfire group of codes.
A control module stores the code when something it watches stays outside what it expects for long enough. On its own the code says which system complained, not which part has failed — the causes below, most likely first, are where to start.
Is it safe to drive with P0340?
Needs attention. Driveable, but starting may become unreliable.
Common causes of P0340
- Failed cam sensor.
- Wiring fault.
- Timing chain wear affecting the signal.
Symptoms
- Long cranking.
- Stalling.
- Rough running.
What to check first
- Sensor signal.
- Connector condition.
- Chain timing.
Can I just clear P0340?
You can, and the light goes out — but a fault that is still there sets the code again, often within a drive or two. Clearing also erases the freeze frame (what the engine was doing when the code was stored) and resets the emissions readiness monitors, so an MOT, smog or inspection test will wait until they have run again. Fix the cause first, then clear it, then watch whether it returns.
Read and clear P0340 from your iPhone with OBDTrip
Plug a Bluetooth OBD-II adapter into the car and OBDTrip reads every stored, pending and permanent code, explains each one in plain English like this, shows what the engine was doing when it was set, and clears the check engine light once the fault is fixed. It keeps a history of when each code comes back, and records every drive on its own from then on.
Needs a Bluetooth Low Energy adapter such as the Vgate iCar Pro — which adapters work with iPhone. Reading and clearing codes is part of an OBDTrip subscription.
Related codes
- P0300 Random/multiple cylinder misfire
- P0301 Cylinder 1 misfire
- P0302 Cylinder 2 misfire
- P0303 Cylinder 3 misfire
- P0304 Cylinder 4 misfire
- P0305 Cylinder 5 misfire
General guidance from OBDTrip's fault-code catalogue, not a diagnosis of your car. When a code points to brakes, steering, overheating or a flashing check engine light, have the car looked at before driving on.