How to Deal with a Crankshaft Position Sensor Failure in a Mercedes
Posted on September 1, 2021 by Keith Cox
Mercedes-Benz is known for producing high-quality, performance-oriented, luxury vehicles. Proper maintenance of these vehicles includes ensuring all sensors are working as they should. One such sensor that is extremely important is called the crankshaft position sensor. If it fails, your Mercedes won’t run properly (if it even starts) and you may experience a range of problematic symptoms that directly impact the driveability of your vehicle.
The crankshaft position sensor functions by monitoring the position of the crankshaft and sending this information to the Powertrain Control Module (PCM), which uses this data to determine when a spark should occur and in which cylinder. Of note is that the spark is a mandatory part of internal combustion engines, used to ignite the air/fuel mixture in the cylinders. Most vehicles have a minimum of 4 cylinders, and they have a specific order of firing.
If this sensor fails, the car cannot run correctly at all, as it is closely involved with one of the most important parts of keeping an engine running. The PCM won’t be able to discern when to ignite the spark and which cylinder needs to fire next, making the car run very rough if it runs at all. The crankshaft itself is the component that helps transform the linear (up and down) motion of the engine to rotational motion, driving the wheels. It’s clear to see why these components/sensors are so necessary to having a running and driving vehicle.
There are multiple signs a crankshaft position sensor might be failing in your Mercedes, and it’s important to be able to recognize them so you can take your vehicle to be serviced as soon as possible to prevent any further damage.
Signs of Failing Crankshaft Position Sensor in Mercedes
- Hard to start: When you start your Mercedes, the crankshaft position sensor begins to work, and if it isn’t functioning properly, the vehicle might be difficult to start or not start at all because the signal either isn’t getting to the PCM or is interrupted.
- Engine stalling: As noted in the previous bullet point, when the sensor is failing, the electronic signal itself might be interrupted, leading to the ceasing of engine activity altogether as the vehicle is unable to determine when to initiate the combustion sequence in any of the cylinders.
- Vibrations: A noticeable increase in vibrations from the engine bay might also indicate the sensor is failing. The vibrations are also usually accompanied by a loss in power and less miles per gallon. A loss of power is typically easy to notice as you’ll feel a lack of acceleration or perhaps a hesitation by the car when you press the pedal. Fuel economy can be checked either by a readout of your current MPG (if your car is equipped) or by monitoring how often you need to refuel on your own.
- Check-engine light: Often the check engine light will appear on your dashboard if a problem is detected with the crankshaft position sensor. The codes that led to the check-engine light can be retrieved using diagnostic scanners that local automotive shops will have.
Noticing any of these signs indicates you need to have your Mercedes serviced immediately. It’s best to have it inspected by mechanics who have training in working on Mercedes and have in-depth knowledge of these cars and how to work on them properly.
Keith Cox Autobahn for Crankshaft Position Sensor Replacement in Mercedes
Keith Cox Autobahn in Bellingham, Washington is your source for German automotive service and repair. We are experts in German vehicles, including Mercedes, and are happy to offer a warranty of 36,000 miles or 36 months on our work, which is three times the length of warranties often given by other businesses!
A free shuttle service is available if needed, and loaner cars are available first come, first served. Before your Mercedes leaves the shop, we will top off all fluids free of charge, as well as wash and vacuum your car, ensuring it comes out looking even better than it did coming into the shop.