The camshaft position sensor on Mercedes vehicles is typically located on or near the cylinder head, close to the camshaft; many engines have one sensor for each camshaft (intake and exhaust) and placement varies by engine family.
Understanding the camshaft sensor's role
The camshaft position (CMP) sensor helps the engine control unit synchronize fuel injection and ignition with the camshaft's position. Accurate readings are essential for timing, idle quality, and overall performance. On Mercedes vehicles, CMP sensors are designed to withstand engine heat and vibration and are wired into the engine's EMS/ECU under the hood.
Typical locations by engine family
These locations cover common Mercedes engine layouts. Check your model's service manual for the exact spot.
- Inline-4 and V6 engines: a CMP sensor is commonly mounted on the cylinder head or the timing cover near one end of the camshaft, with a multi-pin electrical connector.
- Engines with two cams per bank (V6/V8 and some turbocharged engines): there may be two CMP sensors, one for the intake cam and one for the exhaust cam, often located on or adjacent to each camshaft/valve cover.
- Some modern engines position the sensor on the front of the cylinder head, facing the camshaft gear or reluctor wheel, making it accessible without removing the timing chain cover.
- On certain Mercedes engines that share components across models, the CMP sensor can sit behind the timing cover or under the intake manifold, requiring some component removal to reach it.
Note that exact placement varies by model and engine code. When in doubt, consult the official service information for your vehicle.
How to locate the sensor on your specific model
Use these steps to identify the camshaft sensor on your Mercedes model. Start with model and engine code, then inspect the top of the engine for the sensor and its wiring harness.
- Find the engine code and model year to pull the correct diagrams from the maintenance manual or a reputable repair database.
- With the hood open and the engine cooled, remove the engine cover if present to access the top of the cylinder head.
- Trace the wiring harness along the head or timing area to locate a small sensor with a 2- or 3-pin connector mounted on the cylinder head, cam cover, or timing cover.
- Identify whether there is one sensor or a pair (one per camshaft). On engines with dual cam sensors, the second sensor is typically on the opposite side bank.
- Consult factory diagrams to confirm the exact sensor location and any special removal steps if replacement is needed.
If you’re not comfortable locating or testing the sensor, visit a qualified technician. Modern Mercedes use sensitive electronics and timing-critical components; improper handling can cause more issues.
Common symptoms indicating a faulty camshaft sensor
Look for symptoms such as fluctuating idle, engine misfires, reduced power, a check engine light, trouble starting, or a diagnostic trouble code like P0340 or P0341 depending on the specific sensor. If you see these, have the CMP sensor and related wiring tested.
Replacement considerations
When replacing the camshaft sensor, ensure you have the correct part number for your engine code. Replacement typically involves disconnecting the battery, removing the sensor retaining bolt, pulling the sensor out, and cleaning the mounting surface. Some engines require timing checks or relearn procedures after sensor replacement, so follow the service manual and, if in doubt, have a professional perform the job.
Summary
Across Mercedes models, the camshaft position sensor is usually located on the cylinder head near the camshaft, or on the timing cover, and may be one or two sensors depending on whether the engine has a single or dual cam setup. Always verify with model-specific diagrams and service information to locate and replace the exact sensor for your vehicle.