Signal Missing. Permanent Fault

Signal missing. Permanent fault

Checking components
The diagnostic trouble code (DTC) indicates that the communication between the additional heater module and the central electronic module (CEM) is interrupted. This may be due to a fault in the cable between the control modules or a defective communication device in one or both of the control modules.
Check the cable between central electronic module (CEM) connector terminal #18A and additional heater terminal #6. Check for an open-circuit. Check for a short-circuit to ground.

Other information:
- Checking wiring and terminals Checking Wiring And Terminals.













Was a fault detected?

Yes - Verification

No - Replacing the additional heater module

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Replacing the additional heater module
Try a new additional heater control module.

Other information:
- To access or replace the additional heater module, see Control module engine coolant heater, replacing Service and Repair.


Continue - Verification

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Verification




Verification

Verification

Hint: After the repair it is necessary to check that the fault has been rectified.




- Ignition off.
- Connect connectors, install components, etc.
- Ignition on for at least 10 seconds.
Check that diagnostic trouble code status is showing Intermittent.





Is the status of the diagnostic trouble code Intermittent?

Yes - VERIFIED

No - VERIFICATION FAILED

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VERIFIED - Fault Found

VERIFICATION FAILED - Fault-tracing information

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Fault-tracing information




Information

Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.

Do you want to exit fault-tracing?

Yes - FAULT-TRACING FAILED

No - Attempt New Test

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FAULT-TRACING FAILED - No Fault Found

Attempt New Test - Checking components

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