Meaning
The camshaft position sensor tells the computer which cylinder is on the compression stroke. For P0340, the signal is missing or electrically incorrect.
Urgency
Medium to high. Some cars keep going, others misfire or die on the road.
It affects
Petrol and diesel engines. Sensor, wiring, clutch, sometimes gear.
What does P0340 mean
Without a signal from this sensor, the computer does not know exactly when to inject and fire in each cylinder. Many engines go into reserve mode and are guided only by the crankshaft, but it is more difficult to start. If the signal is there but is illogical, the code usually is P0341.
Symptoms
- Difficult or prolonged burning
- Engine stalls, sometimes after warming up
- Power loss, emergency mode
- Rough idle
| Can it be driven?
Carefully. If the car stalls on the road, don't drive it - you lose both power steering and power brakes.
Common reasons
- Faulty sensor — most commonly from heat or oil in the clutch.
- Broken or frayed wire, oxidized coupling.
- Power problem of the sensor (5 V or 12 V).
- Damaged Gear (Reactor) on the camshaft.
- Jumped gear — then it often comes out and P0016.
How we diagnose it
- We check if the computer sees a signal when the engine rotates.
- We measure the power supply, the mass and the signal of the coupling, if necessary with an oscilloscope.
- We check the wiring to the computer.
- If the sensor and cables are fine, we check the gearing.