Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information CEM-U021400

Condition

Applies to vehicles with a system for keyless access
- The control modules communicate with each other for exchange of information in a network via a standardized serial communication procedure - CAN (Controller Area Network).
The diagnostic trouble code (DTC) is stored if the control module detects that:
Interrupted or no communication with the Keyless vehicle module (KVM).
The control module's test for the diagnostic trouble code (DTC) starts in the event of:
- Ignition switch position II.

Note! The control module can only detect the fault once the test has been started and the diagnostic trouble code (DTC) is stored when the conditions are met. The diagnostic trouble code (DTC) indicates a fault in the communication across the CAN network and does not isolate an individual node. Do not replace the central electronic module (CEM) unless fault-tracing indicates a damaged control module.

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.

Applies to vehicles without a system for keyless access
- The Central Electronic Module (CEM) both 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 detects that:
Communication with remote receiver (RRX) is lost.
The control module's test for the diagnostic trouble code (DTC) starts in the event of:
- Ignition switch position II.





Substitute value
- None.

Possible source

Applies to vehicles with a system for keyless access
- Voltage feed to Keyless vehicle module (KVM) missing.
- Open circuit on ground cable to Keyless vehicle module (KVM).
- Contact resistance in the terminals.
- Open-circuit or short-circuit in the wiring for the control area network (CAN).
- Keyless vehicle module (KVM) not intended for this car, e.g., used control module with other hardware/software.

Applies to vehicles without a system for keyless access
- No power supply to the remote receiver module (RRX).
- Open circuit on the ground cable to Remote Receiver Module (RRX).
- Open-circuit in the signal cable to the remote receiver module (RRX).

Fault symptom[s]
- Cannot be operated by remote control
- No keyless functionality
- Tire pressure monitoring. No function.