Short Circuit to Ground / Check Suction Fan Control Module

Electric Suction Fan for Engine or Air Conditioning :: Short Circuit to Ground / Check Suction Fan Control Module

Check Component Electric Suction Fan for Engine or Air Conditioning

Check Component M4/7 (Engine and AC Electric Suction Fan with Integrated Control)

Test 1 Check Component M4/7 (Engine and AC Electric Suction Fan with Integrated Control)
Test 2 Test actuation of component M4/7 (Engine and AC Electric Suction Fan with Integrated Control)
Test 3 Test PWM Signal for Operating the Suction Fan


1 Check Component M4/7 (Engine and AC Electric Suction Fan with Integrated Control)

Test requirement
- CAN communication to control module N22 (AAC pushbutton control module) is o.k.

Test sequence
- Switch off ignition and then switch on.
- Operate engine at idling speed.

Status of the relevant actual values:
- Fan capacity request by air conditioning: Note! Communication with ECU required
- Fan capacity request by engine: Note! Communication with ECU required
- Temperature of coolant: Note! Communication with ECU required
- Air conditioning: Note! Communication with ECU required

- Note: The electric suction fan for engine or air conditioning is off in the case of on/off ratio of 10%, and it runs at maximum speed in the case of an on/off ratio of 90%. When unplugging the socket of component B11/4 (Coolant temperature sensor), the fan capacity request (from engine) rises to > 90%.

Specified values
- Temperature of coolant <80 °C ,Air conditioning OFF : Suction fan STATIONARY
- Temperature of coolant <80 °C ,Air conditioning ON : Suction fan RUNNING
- Temperature of coolant >95 °C ,Air conditioning OFF : Suction fan RUNNING

Question
- Was the test o.k.?
Yes
The test was okay. ** End of Test **
No
The test was not okay.
Possible cause and remedy
- Test actuation of component M4/7 (Engine and AC electric suction fan with integrated control).

** End of Test **


2 Test actuation of component M4/7 (Engine and AC Electric Suction Fan with Integrated Control)

Test requirement
- The engine is running.

Note: Component M4/3 (engine/AC electric suction fan) runs with an on/off ratio of 50 % during the actuations for safety reasons.

Note! Communication with ECU required.


3 Test PWM Signal for Operating the Suction Fan

Test requirement
- CAN communication to control module N19 (Air conditioning pushbutton control module) is o.k.
- Actuation is not okay.

Test sequence
- Switch off ignition.
- Connect socket box (35-pin) to component N3/10 (ME-SFI control module).
- Connect socket box (126-pin) to component N3/10 (ME-SFI control module).
- (5.7) Pin 7 of 35 <--> Pin 124 of 126 (4.39)
- Operate engine at idling speed.

Status of the relevant actual values:
- Temperature of coolant: Note! Communication with ECU required
- Air conditioning: Note! Communication with ECU required

Specified values
- In the case of : Coolant temperature <85 °C, Air conditioning ON : [2.5...12.5] V
- In the case of : Coolant temperature >95 °C, Air conditioning OFF : [2.5...12.5] V

Question
- Are the measured values okay?
Yes
The measured values are o.k.
Further possible causes of fault
- Inspect cables from component N3/10 (ME-SFI control module) to component M4/7 (Engine and AC electric suction fan with integrated control).
No
The actuation was not okay.
Possible cause and remedy
- Inspect cables from component N3/10 (ME-SFI control module) to component M4/7 (Engine and AC electric suction fan with integrated control).

** End of Test **