A6 BiTurbo Cooling fan runs continuously

[palantir65]

Folks -

I got back my A6 C7 - 3.0 BiTurbo (2014) after a waterpump replacement. Coincidence or not, but since that moment my left cornering light stopped working and - worse - one of my cooling fans is running continuously. It starts a few seconds after I unlock the car, and only stops about a minute after I switch it off again.

Surely I did find the posts about the car regenerating, which I recognise. Mine does that as well, but only every few weeks. Now the fan is constantly on though.

A local Specialist with VCDS concluded that the fan control unit is dead. A new costs over €1100. Ex labor. Ouch. He also tells me that this happens "all the time" with the BiTDi. This I find odd, given the complete absence of posts on this topics here on this forum. Am I searching for the wrong keywords perhaps?

So: does anyone recognise this? Is there an alternative fix? Could the control unit itself be fixed? Could it be an accidental wiring / connector issue (given that the waterpump was just replaced)? Does VCDS tell the difference if it's the wiring or the electronics? Can these units be purchased anywhere at a somewhat more affordable price?

Many thanks,
Ronald

[Crasher]

We could do with the fault code information, did he give you a printed report?

[palantir65]

Took a bit of time to get it but here's a pic of the fault detected:
4527 - Coolant Fan Control Circuit 1
P0480 00 [047] - Electrical Malfunction

20190709_180007.jpg

Does that mean anything to anyone?

[Crasher]

Was the engine running during that scan?

[palantir65]

Was the engine running during that scan?

I don’t remember for a fact but I don’t think it was...


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[Crasher]

I was hoping it was running as the zero rpm display would suggest a communications error. I is probably going to be more cost effective to have it put on ODIS using Guided Fault Finding which could pin point the issue within an hour IF there is a planned routine for the fault. Apart from that, someone will have to use the full Basic Equipment and engine current flow diagrams to try and track down the relationship between the two faults (I assume the cornering light problem is still there?) and use the measuring block data to track down the issue. If it wasn’t for the cornering light I would say a stab in the dark guess was the fan controller but with the 4G’s CAN complexity it could be water ingress; this is the sort of fault any non electronic systems trained, experienced and enthused mechanic would run a mile from as it could eat hours of fruitless labour..... conversely it could be instantly obvious to such a person.

For the 4H I found this on Ross Techs site 16864/P0480/001152 - Ross-Tech Wiki , if you follow the link File:2011 RoW A8 3.0 CR TDI CDTA.JPG - Ross-Tech Wiki it may have some similarities

[palantir65]

Thanks Crasher. I did find these pages on the Ross website and also a post on a US website where someone was describing exactly the same issue. He first swapped out the fan controller but in the end it turned out “the ECU”

Question about that: is there only one ECU in the car? When I searched for ECU on one of the many car parts sites, it also showed me a Cooling Fan controller. Kinda like a big relay block. Is that considered an ECU as well and where in the car is it situated? Is it worthwhile swapping that or not at all?

I’ll probably continue by replacing the light bulb. That could actually be the only thing wrong with the cornering light and would rule out a link between the two faults I’m experiencing.

Thanks for the extensive guidance!
Ronald


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[Crasher]

Private message me the cars VIN.

[palantir65]

I PM-ed you my VIN, Crasher.

For any other followers of this thread: another thread I found that is describing exactly what my car is doing too:
Engine Fan Always Running [Archive] - Audizine Forums

"my engine fan sometimes comes on for a few seconds after I open my door while the car is off. This is in addition to the fan always running while my car is running and running between 1-10 minutes after I turn off my car."

Thanks for your help Crasher!
Ronald

[palantir65]

Just to follow up: cornering light is fixed. I had a funky error message on my dash, something like "Headlight control module failure." `Fortunately it was only the bulb. The fan is still running so the two errors seem unrelated...