The customer may complain of a lack of heat in the passenger compartment even if the vehicle has been running for a long period. In the Climatronic control module, one or two DTC codes will be present. Code B10D004 will indicate a coolant circulation pump failure.
Code B11D501 indicates the supply voltage for terminal 30 of the coolant circulation pump has an electrical fault.
To remedy the problem, the V50 coolant circulation pump needs to be replaced.