Faulty Signal

Faulty signal

Checking the power supply








- Ignition off
- Disconnect the connector for the climate control module (CCM)
- Ignition on.
Check the power supply to the climate control module (CCM) by:
- Measuring the supply voltage between terminals #1 (#25) and #16 (#40) on the connector for the climate control module (CCM)
- Measuring the battery voltage.
If the difference is greater than 2 V between the supply voltage for the climate control module (CCM) and the battery voltage, the fault is in the power cable or is due to contact resistance. If this is the case, check the power cable and the connectors.
Check the fuse for the climate control module (CCM). A half burned fuse can cause intermittent faults.

Hint: The climate control module (CCM) is powered via a relay in the central electronic module (CEM).

There may be an internal fault in the climate control module (CCM) if the difference is less than 2 V.
Remedy as necessary.

Other information:
- For further information about the fuses and relays, see the Wiring Diagram
- Connecting the breakout box Connecting the Breakout Box, Climate Control Module (CCM)
- Signal description Signal Description, Climate Control Module (CCM)
- Component location Component Location, Climate Control Module (CCM)
- Climate control module (CCM) Service and Repair
- Checking wiring and terminals Checking Wiring and Terminals





Continue - Verification

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Verification




Verification

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








- Ignition off
- Reinstall the connectors, components etc.
- Ignition on.
Check that the power supply to the central electronic module (CEM) and the climate control module (CCM) does not differ by more than 2 V.





Is the power supply OK?

Yes - VERIFIED

No - VERIFICATION FAILED

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VERIFICATION FAILED - Fault-tracing information

VERIFIED - VERIFIED

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Fault-tracing information

Attempt New Test - Checking the power supply

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