Can't find this part

[Classik]

I have a faulty control unit, the one attached to the secondary cooling fan at the front of the radiator, but I can't find the exact location of this part and its ETKA code. Would someone be kind enough to help?

Many thanks, and merry Christmas to you all!!

[Shoppinit]

Which fan, the big one of the small one?

[Classik]

Wow, fastest response ever!!
The small one. The scan says the secondary cooling fan

[Shoppinit]

viewtopic.php?t=90067

[Classik]

Should have searched better on the forum, thank you very much for your help!
Seems indeed like a recurrent issue. Checked the fuse and relays so the control unit should be faulty. I suppose it's worth trying to get one on flea bay?

[Nobby]

One top tip - if you can’t find any that match the exact part number from the RS6 on eBay and don’t want to fork out shedloads from AUDI then you could get one from another Audi/be etc. When I was looking there were some that were identical, same wires and the pin out is shown on a Sticker on the unit. I may have my old one in the garage somewhere.

[bilko1]

Changed mine along with the fan a few weeks back, controller is £200 fan was £300. There's a piece of rubber that covers the bonnet lock this seems to fall apart with age and can go in to the fan causing the faults. The cover that goes over the lock is no longer available

[Classik]

@Bilko1: in the end, did you know which part was faulty? The ecu or the fan itself?
@Nobby: is your old unit still working?

Surprising how many of these things are failing, is it because they are exposed to the engine heat?

[bilko1]

Original I had an intermittent controller error pop up on VCDS but the fan was working when activated so I ignored it. When I did the cam belt I thought I'd change the controller as the front end was in pieces anyway and the fault had become permanant in VCDS, this got rid of the error code. Just before I put the front end back together I was using VCDS to check the timing and tried to activate the fan and it didn't work. The fan spun freely by hand so I checked the output from the controller which was fine so took fan off (1 screw) powered it up with a power probe and it was dead. New one ordered (back order from Germany) fitted tested all ok.

[Classik]

Thanks for the report, that's helpful.

[Classik]

Quick update : got my hands on a second hand secondary fan ecu, but unfortunately the symptoms remain the same, still got those exact same #@* fault codes : 18393 & 18308, both intermittent. So except very bad luck, seems like the problem lies elsewhere..
Could a faulty fan as above generate such codes? Will also check again the relays just in case. Meanwhile any suggestions are welcome!

Oh and I just got a pair of Waggies installed. First impressions are excellent, but I'll have to have the map updated for those. More later

[Shoppinit]

The error codes are fairly unambiguous. My first suspicion would be that the controller that you bought is also duff. Have you tried clearing the fault codes then using the output tests to manually test the controller / fan?

Could be a bad earth for the fan module. Or a broken wire somewhere between the fuse and the fan. You could try doubling the earth temporarily to see if that cures.

No point mapping for the waggers unless they are part of a more comprehensive set of mods.

[Classik]

Thanks for the unfailing help Shopp. Yes I did clear the faults but they always come back, and yes I definetly need to adopt a more rational approach by checking every link as you proposed above. I'll do as suggested and report.

Mind expanding on the reprog part of your post? As of now, I have upgraded downpipes, 200 cells cats, no precats, Milltek exhaust and of course the recent Waggers. Oh and I have green air filters and a fire extinguisher too! Doesn't it qualify for a remap? And if no, what should be the next step, bigger fuel injectors? R8 coolant cap? Thanks!

[Mɐʇʇ]

Definately R8 Coils.

[Shoppinit]

Thanks for the unfailing help Shopp. Yes I did clear the faults but they always come back, and yes I definetly need to adopt a more rational approach by checking every link as you proposed above. I'll do as suggested and report.

The output test will give useful information.

Mind expanding on the reprog part of your post? As of now, I have upgraded downpipes, 200 cells cats, no precats, Milltek exhaust and of course the recent Waggers. Oh and I have green air filters and a fire extinguisher too! Doesn't it qualify for a remap? And if no, what should be the next step, bigger fuel injectors? R8 coolant cap? Thanks!

Definitely worth getting a custom map done after precats delete and sports cats. A good map should give you around 550-560bhp. The IC or the catback on their own won't give any significant gains. Neither will the air filters. OE paper filters FTW.