General Information
The diagnostic trouble code (DTC) is stored when the communication between the central electronic module (CEM) and the relevant control module has been interrupted. There can be a number of causes for interruptions in the communication:
- Faulty signal configuration in the control module that stored the diagnostic trouble code (DTC). The fault can be due to a customer or workshop replacing a control module without downloading new software for the replacement
- Intermittent open-circuit in one or both CAN cables in part of the network
- Intermittent short-circuits between the CAN cables
- Intermittent short-circuits between one of the CAN cables and ground or supply voltage
- Internal fault in the control module that stored the diagnostic trouble code (DTC).
The fault can also be due to faulty software in a control module, a hardware problem in the CAN network (faulty cables) or a fault in a control module.
If there is a diagnostic trouble code (DTC) for a communication fault in a control module, check whether diagnostic trouble codes (DTCs) have been stored in the central electronic module (CEM). The central electronic module (CEM) monitors the voltage level in the CAN cables and is the only control module that can directly store a diagnostic trouble code (DTC) for a short-circuit in one of the cables for ground or supply voltage. Do not replace the central electronic module (CEM) in the event of a CAN fault unless fault-tracing has indicated that the central electronic module (CEM) has an internal fault.
Corrective actions
- If this diagnostic trouble code (DTC) is the only communication diagnostic trouble code (DTC) stored in one of the control modules in the high speed network, try to remedy the fault by downloading new software for the control module that stored the diagnostic trouble code (DTC)
- Check the cables in the CAN network according to the following fault-tracing
- The control module should be replaced as a last resort.
Other information
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Refer to VERIFICATION