Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information CEM-DD21

Condition




The central electronic module (CEM) transmits and receives information via a standardized serial communication method - LIN (Local Interconnect Network).
The diagnostic trouble code (DTC) is stored if the control module registers serious disruption (LIN communication blocked) in the wiper motor module (WMM) and/or the rain sensor module (RSM).
The diagnostic trouble code (DTC) can be diagnosed at key positions I and II.

Note! In the event of DDxx diagnostic trouble codes (DTCs), the central electronic module (CEM) must not be replaced when the diagnostic trouble code (DTC) indicates a short-circuit in one or more conductors in the LIN network! The central electronic module (CEM) is the only control module that monitors the voltage level in the LIN wiring. The central electronic module (CEM) is therefore the only control module that can store a diagnostic trouble code (DTC) for a short-circuit in one of the cables to ground or supply voltage. Do not replace the central electronic module (CEM) in the event of a LIN fault unless VIDA fault-tracing has indicated that the central electronic module (CEM) has an internal fault.

Substitute value
- The windshield wipers operate at high speed for 5 minutes
- The windshield wipers operate at low speed for 5 minutes
- The windshield wipers operate at short intervals for 5 minutes
- The windshield wipers stop.

Possible source
- Short-circuit between the LIN wiring
- Open-circuit in the LIN wiring
- Internal fault in the control module
- Internal fault in another control module in the same part of the LIN network.

Fault symptom[s]
- No rain sensor function
- The windshield wipers are not working.