Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information CEM-DE29

Condition




The diagnostic trouble code (DTC) is stored if the central electronic module (CEM) registers that communication with the climate control module (CCM) is not operating.

Note! In the event of CEM-DEXX diagnostic trouble codes (DTCs) being stored the central electronic module (CEM) must not be replaced; the diagnostic trouble code (DTC) indicates a communication fault in the Control area network!

The diagnostic trouble code (DTC) can be diagnosed when the ignition has been on for at least 10 seconds.

Substitute value
- None.

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

Note! In the event of missing CAN communication, but with the power supply still on, the climate control module (CCM) will function for a few minutes after the key has been removed (Limp-home function).

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]
- The climate control system does not function at all
- The climate control system functions after the key has been removed
- The function button is not working.