P0340 on a BMW: Causes, Fixes & Repair Cost

⚠️ Severe · not recommended to drive

The engine may not start, or it may stall while driving, so have the car towed if it won't start.

What P0340 means on a BMW

On a BMW, P0340 means the engine computer is getting no signal or a bad signal from the camshaft position sensor. Without camshaft position, the computer can't time fuel injection and valve timing correctly, and the engine may refuse to start or may stall.

Is P0340 common on BMWs?

P0340 shows up on BMWs with the inline-six engines, most often the 3 Series, 5 Series, X3, and X5. The camshaft position sensor mounts at the front of the valve cover, and sensor failure is the usual cause. Oil leaking from the valve cover gasket onto the sensor or connector is also common on these engines.

Commonly reported on: 3 Series, 5 Series, X3, X5.

Symptoms

Check engine light is on
Engine cranks but won't start
Engine stalls while driving
Rough running or loss of power

Common causes

most common: Failed camshaft position sensor
common: Oil leaking onto the sensor or connector from the valve cover gasket
common: Damaged wiring or connector at the sensor
less common: Timing chain or VANOS timing issues

How to fix it

Fix	DIY?	Typical cost
Replace the camshaft position sensor	Yes	$60–180
Replace the valve cover gasket if oil is leaking onto the sensor	Mechanic	$250–600
Repair damaged sensor wiring or connector	Mechanic	$100–300