Fault-Tracing Information

Fault-tracing

Checking communication




The diagnostic trouble code is stored when communication between Central electronic module (CEM) and relevant control module has been interrupted. There can be a number of causes for interruptions in the communication:
- Incorrect signal configuration in control module that set diagnostic trouble code. 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.

Note! 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). Central electronic module (CEM) monitors the voltage level on the CAN-lines, and is the only control module that directly can set a diagnostic trouble code for short-circuiting to ground or to voltage for any of the leads. Central electronic module (CEM) shall not be replaced in case of CAN-fault, unless troubleshooting reveals that the module has an internal fault.

Corrective actions
- If the problem is intermittent, erase the diagnostic trouble code and check that it is not generated again.
- If there are diagnostic trouble codes stored in several control modules that indicate lost communication on the CAN-net, first try to troubleshoot diagnostic trouble codes in Central electronic module (CEM).
- If there are only diagnostic trouble codes that indicate lost communication on the CAN-net stored in the control module that generated this trouble code, try to solve the problem by downloading new software to the control unit.
- Check the cables in the controller area network (CAN) according to the following fault-tracing.

Other information
- Checking wiring and terminals Checking Wiring and Terminals. Permanent Faults
- For further information, see the wiring diagram.

Continue - Verification

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Fault-tracing information

Attempt New Test - Checking communication

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Verification




Verification

Hint: After carrying out the repair check that the fault has been remedied.




- Reinstall the connectors, components etc.
- If the battery negative lead has been removed:
Connect the battery negative lead.
- Switch on the ignition. Wait 10 seconds.
Read diagnostic trouble codes by clicking the VCT2000 symbol.
If the fault is intermittent, the fault has been remedied.





Is the fault intermittent?

Yes - VERIFIED

No - VERIFICATION FAILED

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VERIFICATION FAILED - Fault-tracing information

VERIFIED - FAULT FOUND

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