Complaint
Only the demister function is available.
The following fault entries may be stored in this context:
9C4A - Motor backpressure
9C8B - Auxiliary heating LIN communication
9C7F - Auxiliary heating communication
9C56 - Third seat row
9C4D - Blending motor, left
9C4B - Footwell motor, left
9C4F - Ventilation motor, right
9C4C - Footwell motor, left
E708 - LIN bus fault
9C4E - Ventilation motor, left
9C48 - Demister motor
9C50 - Blending motor, right
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Cause
The clean-air duct is leaking. Water ingress leads to failure of the backpressure
compensation stepper motor and, in due course, to corrosion of the connector on the stepper motor and blower motor.
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Measure
Check whether the failure is caused by water ingress via the fresh air duct (see
example picture in the attachment - water marks).
If the failure was caused by water ingress, replace the clean-air duct and the defective stepper motor,
and any other components damaged by the water, with the latest replacement part.
The current part numbers are:
64 31 6 945 577 CLEAN-AIR DUCT, LHD
64 31 6 945 578 CLEAN-AIR DUCT, RHD
64 11 6 956 706 STEPPER MOTOR EFB 32X (ASIC C)
64 11 6 971 108 IHKA BLOWER ASSY LHD
64 11 6 971 109 IHKA BLOWER ASSY RHD
