A4/A6 Doku: Faulty Fan Control System (Solution)

The electric fan is either not working or running constantly, which in the first case causes the coolant temperature to become too high, and in the second case prevents the engine from starting due to a dead battery.

Affected vehicle identification numbers (VINs):
4B 2N000000 - 122503
8E 2A000000 - 292676


Cause:
Component defect in the control unit for the electric fan.

Solution:
In order to reliably eliminate the error, it is necessary to differentiate between various types of error manifestations.

Case 1:
The electric fan is not working, which causes the coolant temperature to become too high. There is an error code stored in the fault memory related to the fan control unit.
In this case, the control unit for the radiator fan needs to be replaced. Component defects can occur in control units that were manufactured up to production date 212 of the year 2002.

Case 2:
The vehicle won't start due to a dead battery, or alternatively, the fans continue to run even after the system has shut down (the runtime is a maximum of 12 minutes).

Procedure:
1. Kontrolle des Stromversorgungsrelais für das Motorsteuergerätes J271 auf Funktion. GPlease provide the text you would like me to translate from German to English. I need the text to be able to give you a translation.
2. Inspect the wiring connected to terminal 87 in the fuse box for any damage to the insulation.
3. Check the electrical box for water ingress.