18308 - Coolant Fan Control 2

[GlynH]

Hello again,

Second post asking for more advice on another 'under the bonnet' error on my 2005 A8 W12

18308 - Coolant Fan Control 2
P1900 - 004 - Open or Short to Ground

I had a problem last week where after a run I shut the engine off but the cooling fan continued to run. Now I never usually notice the fan running at all during normal running and certainly not when switching the engine off.

The temperature gauge has always sat exactly on 90 but when the fan is running the gauge drops to @75 or so as might be expected.

This doesn't happen all the time…for example yesterday was fine, this morning was fine but this afternoon it started again.

Now I can stop the fan by pulling the fan control fuse in the drivers side fusebox as a temporary measure after switching the car off but I would like to know exactly what the fault is and where I might look to resolve the issue.

Thanks & kind regards,
-=Glyn=-