Cruise Control: Testing and Inspection

Fault Value Received
The fault "0xD17C fault value received" is stored in the ACC/LRR control module.

Explanation:
For the ACC function, information from partner control modules is essential. The partner control modules transmit this information via CAN messages to the ACC/LRR control module. The fault is entered if the relevant partner control module sends a default value or invalid ID in the relevant message ACC/LRR control module instead of the required information and this impairs the ACC function. In this case, a fault memory entry should also be made in the corresponding partner control module. The relevant partner control module (= sender of this message) is displayed in the test module at the bottom.

Example: The engine control module detects that the calculated torque is incorrect due to a system fault. It still sends the corresponding message, but this time with an invalid ID or a default value.

Fault effect: The defective information from the partner control module means that the ACC/LRR control module switches off and interrupts accelerating.

For this fault, the cause does NOT lie in the ACC/LRR control module or in the ACC software!

Read the fault memory of the relevant partner control module and continue troubleshooting according to test plan in the relevant partner control module. Delete fault codes in ACC/LRR control module.

If work is currently being carried out on the vehicle and this causes the fault, under certain circumstances the corresponding fault memory entry can only be made in the partner control module after a terminal change. If necessary, run a terminal change.

If no fault is saved in the relevant partner control module, it can be assumed that there is a sporadic fault. There is no repair measure available for this case: Delete fault codes in ACC/LRR control module.

Note on clearing the fault memory
Under certain circumstances, the fault in the ACC/LRR control module 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.