P0340 on a Mercedes-Benz: 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 Mercedes-Benz

On a Mercedes-Benz, 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 correctly, and the engine may refuse to start or may stall.

Is P0340 common on Mercedes-Benzs?

P0340 shows up on Mercedes-Benz models with higher mileage, often C-Class, E-Class, GLK, and M-Class vehicles with four-cylinder or V6 engines. The camshaft position sensor or its magnet ring fails with age, and oil contamination near the front of the engine can also cause it.

Commonly reported on: C-Class, E-Class, GLK, M-Class.

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: Damaged wiring or connector at the sensor
common: Oil or debris on the sensor face
less common: Timing chain or timing issues

How to fix it

Fix	DIY?	Typical cost
Replace the camshaft position sensor	Yes	$70–200
Repair damaged sensor wiring or connector	Mechanic	$150–350
Have a mechanic check the timing chain and guides	Mechanic	$1000–1800

Frequently asked questions

Will my Mercedes-Benz start with a P0340 code?

It may not. A lost camshaft position signal can stop the engine from starting or make it stall. If it won't start, have it towed to a shop.

What usually causes P0340 on a Mercedes-Benz?

The camshaft position sensor fails with age and mileage. Wiring problems at the sensor are the next most common cause.

How much does it cost to fix P0340 on a Mercedes-Benz?

A new camshaft position sensor plus labor is about $150–350 on most Mercedes-Benz models. Timing chain repairs are far more expensive but less common.