Diagnostic Trouble Code (DTC) Information CEM-U042387: Notes

Condition 

The control modules communicate with each other for exchange of information in a network via a standardized serial communication procedure - CAN (Controller Area Network).

The diagnostic trouble code (DTC) is stored if the control module detects that:

• No communication with the Driver information module (DIM).

The control module's test for the diagnostic trouble code (DTC) starts in the event of:

• Ignition switch position I and II.
• Interior lighting relay is activated.

Substitute Value 

• The function switches off permanently after 100 operating cycles where the fault was detected. Erasing diagnostic trouble codes (DTCs) resets the result.

Possible Source 

• Open-circuit in the CAN cables between the control module and the Central Electronic Module (CEM).
• Internal error in Driver information module (DIM).

HINT: If several diagnostic trouble codes (DTCs) are stored in the central electronic module (CEM) for communication faults with other control modules in the low speed network, this indicates a common fault in the Control area network. Do not replace the Central electronic module (CEM) unnecessarily. 

Fault symptom[s] 

• Start inhibitor not operating