No Communication

No communication

Checking the diagnostic trouble codes (DTCs)




- Ignition on.
The diagnostic trouble code (DTC) can occur together with diagnostic trouble codes (DTCs) for other components that communicate with the climate control module (CCM) via LIN bus 1 and LIN bus 2.
Check whether the diagnostic trouble code (DTC) has been stored together with other diagnostic trouble codes (DTCs) for other components on the climate control unit.
Select one of the following options:
1. The diagnostic trouble code (DTC) is together with diagnostic trouble codes (DTCs) for components in both LIN bus 1 and LIN bus 2 (CCM-DD12-CCM-DD18, CCM-DD31-CCM-DD34)
2. The diagnostic trouble code (DTC) is together with diagnostic trouble codes (DTCs) for components only on LIN bus 1 (CCM-DD31-CCM-DD34)
3. The diagnostic trouble code (DTC) is not together with diagnostic trouble codes (DTCs) for other components on LIN bus 1 and LIN bus 2.

Select an alternative.

1 - Checking the connectors and wiring

2 - Checking LIN bus 2 and connector

3 - Checking the wiring and component

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Checking the connectors and wiring








- Ignition off
- Disconnect the connector for the climate control module (CCM)
- Disconnect the connector for the central electronic module (CEM)
- Ignition on.

Checking the power supply and ground terminals
The following applies to components on the climate control unit that communicate with the climate control module (CCM) via LIN bus 1 and LIN bus 2:
- All components are jointly powered via a fuse from the central electronic module (CEM)
- All components are grounded via a common ground terminal.
Check the power supply to the components on the climate control unit by taking a reading on connector A for the central electronic module (CEM) between terminal #A44 (C44) and chassis ground.
Also check the fuse on the central electronic module (CEM).
Check the power supply cable between the central electronic module (CEM) and the connector for the climate control unit. Check for an open-circuit. Measure between terminal #1 on the connector for the climate control unit and chassis ground.
Check the ground terminal for the components on the climate control unit. Measure between the connector for climate control unit terminal #4 and chassis ground.
Check the connector for the climate control unit and connector A for the central electronic module (CEM). Check for contact resistance. Check for oxidation. Check for loose connections.

Checking LIN bus
Check both LIN bus 1 and LIN bus 2. Check for an open-circuit.
Take readings between:
- The connector for climate control module (CCM) terminal #12 (#36) and the connector for climate control unit terminal #3
- The connector for climate control module (CCM) terminal #7 (#31) and the connector for climate control unit terminal #6.
Check the wiring between the connector and the components on the climate control unit. Check for an open-circuit.
Remedy as necessary.

Other information:
- For further information about the connectors, fuses and relays, see the Wiring Diagram
- For connection of the breakout box to the Climate control module (CCM): Connecting the breakout box Connecting the Breakout Box, Climate Control Module (CCM)
- For connecting breakout box to Central Electronic Module (CEM): Connecting the breakout box Connecting the Breakout Box, Central Electronic Module (CEM)
- 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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Checking LIN bus 2 and connector




- Ignition off
- Disconnect the connector for the climate control module (CCM).
Check the climate control module (CCM) connector. Check for contact resistance. Check for oxidation. Check for loose connections.
Check LIN bus 2 between the climate control module (CCM), the connector for the climate control unit and the seat heating module (SHM) left. Check for an open-circuit.
Take readings between:
- The connector for climate control module (CCM) terminal #7 (#31) and the connector for climate control unit terminal #3
- The connector for climate control module (CCM) terminal #7 (#31) and connector A for seat heating module (SHM) left terminal #4.
Check LIN bus 2 between the components (the damper motors and the air quality sensor (AQS)) and the connector for the climate control unit. Check for an open-circuit.
Check the connector for the climate control unit. Check for contact resistance. Check for oxidation. Check for loose connections.
Remedy as necessary.

Other information:
- For further information about the connectors, 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
- Seat Heating Module (SHM) Service and Repair
- Checking wiring and terminals Checking Wiring and Terminals





Continue - Verification

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Checking the wiring and component




- Ignition off
- Disconnect the connector for the air quality sensor (AQS)
- Ignition on.
Check the connector for the air quality sensor (AQS). Check for contact resistance. Check for oxidation. Check for loose connections.
Check that the air quality sensor (AQS) is connected to the power supply and ground.
Measure the voltage on the connector for the air quality sensor (AQS) between terminals #1 and #3.
Check LIN bus 2 by taking a reading between sensor connector terminal #2 and the connector for climate control unit terminal #6. Check for an open-circuit.
Try replacing the air quality sensor (AQS) if no fault is found.
Remedy as necessary.

Other information:
- For further information about the connectors, 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
- Air quality sensor, L.H.D 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 relevant diagnostic trouble code (DTC) has switched status from permanent to intermittent fault.
Check also that diagnostic trouble code CCM-0070, CCM-0071 or CCM-0072 have not been generated in connection with an identification of damper motors.
These diagnostic trouble codes can only be generated in connection with an identification of damper motors and means that identification has failed for some reason.
Remedy by attempting to identify the damper motors again. Alternatively fault-trace the relevant diagnostic trouble codes (DTCs).





Has the status of the diagnostic trouble code (DTC) changed?

Yes - VERIFIED

No - VERIFICATION FAILED

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VERIFIED - FAULT FOUND

VERIFICATION FAILED - Fault-tracing information

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Fault-tracing information

Attempt New Test - Checking the diagnostic trouble codes (DTCs)

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