1A5X - 12

Condition







Diagnostic trouble codes (DTCs) are stored if the central electronic module (CEM) registers that communication with the upper electronic module (UEM) is not operating.

NOTE: In the event of CEM-1A5X diagnostic trouble codes (DTCs), the central electronic module (CEM) must not be replaced as the diagnostic trouble code (DTC) indicates a communication fault in the Control area network.

Substitute value

- None.

Possible source

- No power supply to the upper electronic module (UEM).
- Open-circuit in the ground lead to the upper electronic module (UEM).
- Contact resistance in the terminals.
- Open-circuit in the wiring for the CAN low speed network to the upper electronic module (UEM).
- The upper electronic module (UEM) is not intended for this car (for example a used control module with different software/hardware.

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, see the wiring diagram.

Fault symptom[s]

- Cannot be controlled with the remote control.
- The power sun roof does not operate.
- The interior lighting does not work.