The rain sensor is a driver assistance system which takes the strain off the driver by automatically activating the windshield wiper system when it rains and thereby significantly improving in-vehicle safety and comfort. In the mid-1990s, the rain sensor started to be fitted in vehicles and since then has been a permanent feature of modern vehicle electronics.

If the error message "SCBS / City emergency stop assistant forward gear malfunction" is displayed on the instrument cluster on the vehicle models mentioned above, one cause for this may be a defective boost pressure sensor.

If loud, booming noises are heard from the rear of the vehicle, defective rear wheel bearings may be the cause. 
The rear wheel bearings may have been damaged by a design-related malfunction of the rear wheel brakes during assembly.

With the above-mentioned vehicle, it may happen that the vehicle interior monitoring system, every so often, triggers the vehicle alarm. A faulty ultrasonic sensor of the vehicle interior’s lamp unit is a possible cause.

The classic low beam is in fact a compromise solution, and it's not without its weaknesses. Thanks to its new light functions, the Advanced Front Lighting System (AFS) eliminates the rigid boundaries of the low beam, thereby significantly improving visibility in the dark and in poor weather.

In the above-mentioned vehicles, a software error may cause one headlamp to remain sporadically on after the lights have been switched off.

If the fault mentioned above is detected, it may be in connection with the triggering of the fuel cut-off switch. A fuel cut-off switch is installed in this vehicle. The switch is triggered in the event of a sudden change in the vehicle's position and if any strong vibrations occur.

The following problem is observed on the vehicles mentioned above. During navigation, the display may malfunction (e.g. delayed image display).

The primary task of the exhaust system is conducting the combustion gases of the engine past the driver's cab into the open air. Noise caused by combustion is reduced to the permissible volume by integrated mufflers. 

If the engine of the above-mentioned vehicle only starts after the starter motor has been operated for a longer period of time, a faulty crankshaft sensor may be responsible for this. Crankshaft sensors are used to determine the speed and crankshaft position.

A loss of engine power and rough idling in the vehicles mentioned above may be caused by defective injection valves. An additional stored error code P0093 indicates that there is a pressure drop in the fuel system.

An undefinable buzzing noise heard in the vehicles mentioned above when the air conditioning is switched off may be caused by the air conditioning compressor. The buzzing noise occurs when the engine is at idle speed and may be caused by an internal voltage fault in the compressor.