Fan control, function - GF07.61-P-3023AMG

ENGINE 156.980 in MODEL 164, 251 up to Model Year 8

ENGINE 156.982 in MODEL 209

ENGINE 156.983 in MODEL 211, 219

ENGINE 156.984 in MODEL 216, 221 up to Model Year 8

Fig 1: Identifying Fan Control CAN Communication Diagram

Courtesy of MERCEDES-BENZ USA

The ME-SFI [ME] control unit indirectly actuates the electric suction fan engine and AC continuously.

The fan specified speed is transmitted by the ME-SFI [ME] control unit via a PWM signal (pulse width modulated signal).

The duty cycle of the PWM signal is 10 to 90 %.

Meaning:

10% Electric suction fan "OFF"

20% Electric suction fan "ON", minimum speed

90% Electric suction fan "ON", maximum speed

The AAC [KLA] control unit transmits the status of the automatic air conditioning via the CAN data bus to the ME-SFI [ME] control unit. The fan specified speed is dependent on this and on the coolant temperature.

The engine and AC electric suction fan runs on for up to 5 minutes at "Ignition OFF" if the coolant temperature, the engine oil temperature or the temperature of the ME-SFI [ME] control unit exceeds specified maximum values.

If the battery voltage drops excessively during this operation, engine-off running is suppressed.

Fan emergency operation

If actuation is faulty, the engine and AC electric suction fan runs at maximum rpm.

Component description for the coolant temperature sensor	B11/4	GF07.04-P-6040AMG
Component description for the crankshaft Hall sensor	B70	GF07.04-P-6220AMG
Component description for the ME-SFI [ME] control unit	N3/10	GF07.61-P-6000AMG