A defect in the control unit or instrument cluster can - depending on the type of function control - cause a wide variety of symptoms on the vehicle: illumination of a warning light or sounding an acoustic signal, failure of specific functions (soft top, cruise control, navigation system), modified braking and driving behavior in exceptional situations (ABS, ASR, ESP), problems with the gear shift (transmission control), the vehicle will not start or runs out while driving, sporadic misfiring, low engine power, increased fuel consumption, increased or fluctuating idle speed, engine jerks and / or stutters, total failure and a variety of other, at times complex fault patterns, which sometimes occur only sporadically.
In addition to defects in the control unit numerous other faulty components or a disturbed communication in the electronic system can cause the symptoms you may have.
Sporadic errors are difficult to be reproduced in a test, the localization of their origin may be a challenge. Interdependent faults or failures can occur, in these cases an accurate fault diagnosis is often only possible directly on the vehicle.
A troubleshooting should gradually narrow down possible causes and begin with a detailed error description and list of all symptoms.
last update: 19.3.2019