Red Flags of a Failing Crankshaft Position Sensor in Mercedes-Benz

Modern Mercedes-Benz vehicles are characterized by their efficiency, good driving qualities and engineering. In order to maintain this quality, there are many sensors that are aimed at efficient engine operation. The crankshaft position sensor is one of the most critical ones.

This sensor controls the position and the speed of rotation of the crankshaft and passes this information to the engine control unit. This information is necessary for the control of ignition and fuel supply. When the sensor starts to fail then it affects the engine operation and causes various problems. Identifying the symptoms will help to prevent failures.

Crankshaft Position Sensor Functions

A crankshaft position sensor is an essential part of the engine. This device is responsible for monitoring the crankshaft's location and rotation speed and passing the data to the engine control unit. In turn, the engine control unit knows when it should provide the fuel supply and spark generation. The lack of proper data transmission from the crankshaft position sensor causes the engine to malfunction or to shut down.

What Can Cause a Crankshaft Position Sensor to Stop Working?

Like any other automotive device, a crankshaft position sensor can get old and worn out with time. Some of the reasons for the sensor malfunction are:

• High engine temperature

• Damage to the electrical wiring

• Oil contamination

• Humid environment

• Vibration impact

• Internal electronic malfunction

• Aging

Difficulty Starting the Engine

One of the first symptoms of a bad crankshaft position sensor is problems cranking the engine. This sensor gives the ECU the necessary information to set the proper timing for ignition.

If this signal weakens or becomes intermittent then the car engine will keep cranking for a long time before the engine starts working. In certain instances, the car will not start at all.

A driver can overlook occasional problems with cranking because of a poor battery or fuel. But if the problem persists, one has to check the crankshaft position sensor.

Symptoms are as follows:

Engine stalling without warning

A malfunctioning crankshaft position sensor may result in unexpected engine stalling when the car is moving. With time, the sensor starts delivering faulty information to the ECU or stops sending any signals altogether. In such cases, the ECU loses control over crankshaft position and leading to interruptions in fuel delivery or timing of ignition.

Engine stalling may happen:

• At idle

• During acceleration

• At cruise speed on highways

• When the engine warms up

Illuminated Check Engine Light

The check engine light is among the most common indicators that there is something wrong with the sensors. When the ECU picks up problems with the crankshaft position sensor signals then it will store trouble codes and cause the indicator light on the dashboard to turn on. While the check engine light might mean many things but it should not be neglected.

Rough Idling

Mercedes-Benz cars are designed to idle smoothly. If you start noticing excessive vibration of your car while it is standing still then one of the causes could be a faulty crankshaft position sensor.

Signals from an improperly working sensor could create interruptions in the engine timing and fuel injection process which will consequently result in engine problems.

Symptoms of rough idling might include:

• RPM changes

• Engine vibrations

• Vibrating when stationary

• Uneven engine noise

• Intermittent stalling at idle

Reduced Engine Performance

A damaged crankshaft position sensor might influence engine performance as well. Since the ECU relies on accurate information about the crankshaft so any disturbance in its functioning will make the system work ineffectively. The engine will show signs of poor acceleration and lack of responsiveness.

Symptoms of poor performance might include:

• Slow acceleration

• Low throttle responsiveness

• Power deficiency when overtaking

• Engine hesitation

• Bad driving experience

Poor Fuel Efficiency

Incorrect readings by the crankshaft position sensor could negatively affect the fuel injection timing. This is where the ECU tries to inject more fuel than needed to compensate for poor efficiency.

Frequent visits to the filling station despite no change in your driving behavior might indicate some fault in the sensor.

Fuel economy issues may present themselves in the form of:

• High fuel usage

• Low miles per gallon

• Rich fuel mixture situation

• Smelling fuel in the exhaust

Conclusion

If you find yourself experiencing any of these signs, it is time for your car to be checked out by some experienced mechanics. Whenever your Mercedes-Benz needs professional diagnosis and repair, count on us to perform proper checks and repairs. Our experienced mechanics use state-of-the-art diagnostic tools to identify and solve your problems with the crankshaft position sensor. Come to us now and allow us to help you ensure smooth operation of your Mercedes-Benz in the years to come.

DreamCars Auto Repair is a specialized European Auto Repair shop and parts store in the High Desert of Hesperia, CA. It is a AAA approved facility & the only authorized Bosch service center in the High Desert with highly trained ASE