Initial Inspection and Diagnostic Overview

Troubleshooting Manual For Interface Faults

This Troubleshooting Manual is relevant if an interface fault is stored in the control unit.

Interface fault in control unit
For the control unit function, information on partner control units is essential. The fault is entered if the relevant partner control unit (= interface to control unit) sends a substitute value or an invalid ID instead of the required information, thus impairing the control unit function. In this case, a fault entry should also be made in the corresponding partner control unit.
For this fault, the cause does NOT lie in the control unit which stores the interface fault, or in its software.

Possible fault causes:
- The relevant partner control unit is not yet operational.
- The sensor system of the relevant partner control unit is defective.
- General fault of the partner control unit

Measures
Read out fault code memory of corresponding partner control unit and continue troubleshooting in partner control unit according to test schedule. Delete fault in control unit.

Notes on the DSC control unit:
If repair work is currently being carried out on the vehicle and this causes the interface error in the DSC, under certain circumstances the corresponding fault entry can only be made in the partner control unit after a terminal change. If necessary, run a terminal change. If no fault is stored in the partner control unit, it can be assumed that a sporadic fault has occurred. There is no repair measure available for this case: Delete the fault in the DSC control unit.

Clear fault memory note in DSC control unit.
Under certain circumstances, the fault in the DSC can only be deleted after a terminal change. In this case, switch the ignition off, wait 10 seconds, switch the ignition on again and then delete the fault.