Signal Too High / Signal Too Low

Signal too high / Signal too low

Checking the cable








- Ignition off
- Disconnect the connector for the climate control module (CCM)
- Ignition on.
Check LIN bus 2. Check for a short-circuit to supply voltage.
Take a reading on the connector for the climate control module (CCM) between terminals #7 (#31) and #1 (#25).
If there is a short-circuit to supply voltage in LIN bus 2, continue fault-tracing by locating where the short-circuit has occurred as follows:
- Disconnect the connector on the climate control unit that connects LIN bus 2 from the climate control module (CCM) to other components on the climate control unit
- Check the section of LIN bus 2 that connects the climate control module (CCM) to the right-hand seat heating module (SHM) and the connector on the climate control unit. Take a reading on the connector for the climate control module (CCM) between terminals #7 (#31) and #1 (#25).
If the fault persists, fault-trace LIN bus 2 between the climate control module (CCM), the right-hand seat heating module (SHM) and the connector on the climate control unit. Check for a short-circuit to supply voltage.
If the fault is no longer present, fault-trace LIN bus 2 between the connector and the components on the climate control unit. Check for a short-circuit to supply voltage.
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





Was a fault detected?

Yes - Verification

No - Checking the cable

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Checking the cable




- Ignition off
- Disconnect the connector for the climate control module (CCM).
Check LIN bus 2. Check for a short-circuit to ground.
Take a reading on the connector for the climate control module (CCM) between terminals #7 (#31) and #16 (#40).
If there is a short-circuit to ground in LIN bus 2, continue fault-tracing by locating where the short-circuit has occurred as follows:
- Disconnect the connector for the climate control unit that connects LIN bus 2 from the climate control module (CCM) to the other components on the climate control unit
- Check the part of the LIN-bus 2 that connects Climate control module (CCM) to Seat heating module (SHM) right and the connector on the climate module.
Take a reading on the connector for the climate control module (CCM) between terminals #7 (#31) and #16 (#40).
If the fault persists, fault-trace LIN bus 2 between the climate control module (CCM), the left-hand seat heating module (SHM) and the connector on the climate control unit. Check for a short-circuit to ground.
If the fault is no longer present, fault-trace LIN bus 2 between the connector and the components of the climate control unit. Check for a short-circuit to ground.
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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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 cable

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