Diagnostic trouble code (DTC) information CEM-DD31
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 generated if the control module registers serious interference (LIN communication blocked) with the left camera module (LCM).
The diagnostic trouble code (DTC) can be detected when the ignition switch in position II for at least 10 seconds if battery voltage is above 10.5 V.
Note: In the event of CEM-DDxx diagnostic trouble codes (DTCs), the central electronic module (CEM) must not be replaced as 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 generate 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 fault-tracing has indicated that the central electronic module (CEM) has an internal fault.
Substitute Value
- Nothing.
Possible Source
- Short-circuit between the LIN wiring
- Open-circuit in the LIN wiring
- Internal fault in another control module in the same part of the LIN network.
Fault symptom[s]
- The LED does not come on.