M57/M67 – Electric engine fan control

Electric engine fan control calculates the setpoint speed for the electric fan.

The engine-fan setpoint speed is derived from a characteristic curve as a function of:
• Water temperature
• Current road speed

The fan output stage requested by the air-conditioning control unit via the CAN bus is also taken into account as a variable.

Fan run-on after engine shutdown is limited by either the coolant temperature or a maximum run-on time.
A dummy value is used if the coolant temperature sensor is defective.