Coolant Fans -V7- and -V177-, Checking

Coolant fans -V7- and -V177-, checking





Special tools and equipment
^ V.A.G 1526 A
^ V.A.G 1527 B
^ V.A.G 1594 A
^ V.A.G 1598/31
^ VAS 5051 with VAS 5051/1

Work sequence
- Connect up vehicle diagnostic, testing and information system VAS 5051 and select vehicle system "01. Engine electronics" from list. Ignition must be on.





Indicated on VAS 5051:
- From list -1- select diagnostic function "03 - Final control diagnosis".
- Touch > key, until the radiator exhaust control 2 is activated.
^ Coolant fan control (FC) control module 2 -J671- slowly switches coolant fan -2- -V177 (right) once up to full speed.
^ Touch > key, until the radiator exhaust control 1 is activated.
^ Coolant Fan Control (FC) control module -J293- slowly switches coolant fan -V7- (left) once up to full speed.
- Terminate function "03- Final control diagnosis" by touching 4 key.
If fan actuation does not react as described:
- Based on the previously mentioned criteria, create preconditions for radiator fan start-up (e.g. switch on air conditioner, increase engine temperature accordingly).





Indicated on VAS 5051:
- From list -1- select diagnostic function "08- Reading measured value block".





Indicated on VAS 5051:
1. Enter display group
- Use keypad -2- to enter "135" for "Display group number 135" and confirm by touching Q key.





Indicated on VAS 5051:
- Check display in zones -2- and -3-.
^ Duty cycle of fan 1 (left): min. 10%
^ Duty cycle of fan 2 (right): min. 10%

Note: In the event of fan request from air conditioner and/or if coolant temperature is greater than 98°C, duty cycle must increase to more than 10% and fans must start up.

If duty cycle does not increase to above 10W
- Read out fault memory of engine control module.
- Eliminate any faults displayed.
If relevant fan does not start up although duty cycle is above 1 OW
- Check coolant fan.