cooling fans

[blue28]

Hi all, regular guest but 1st post so be gentle with me,have a problem with fans running high speed constantly with engine on  wether hot or cold, been checked out at dealers +,independent vw in brum replaced sensor and wiring to ecu  but not cured it so its looking  like a new ecu,hence post in wanted section as apparently these can't be repaired  !!   Any ideas would be welcome ,cheers blue 28. Ps car hasn't been remapped + has only done 39000 miles

[edd666999]

Hi all, regular guest but 1st post so be gentle with me,have a problem with fans running high speed constantly with engine on  wether hot or cold, been checked out at dealers +,independent vw in brum replaced sensor and wiring to ecu  but not cured it so its looking  like a new ecu,hence post in wanted section as apparently these can't be repaired  !!   Any ideas would be welcome ,cheers blue 28. Ps car hasn't been remapped + has only done 39000 miles

which sensor did they replace?

[blue28]

Hi ya, I replaced sensor on side of cyl head they replaced the one on outlet pipe ,still throwing up g83 fault code though

[gigolo456]

Im assuming they replaced yr cooling sensor?? Do you know if BOTH yr fans actually work, big and small one?

[blue28]

Yes both sensors replaced, both fans running .

[gigolo456]

Hmmm, strange, does yr temp sit constantly at 90 degrees once engine warm??

[blue28]

Yes sits nicely on 90 no hint of overheating,but worried the fans will let go sooner or later

[john87]

Maybe a silly question, but is your AC switched on?

[blue28]

A/c on or off still runs ,checked all that  ,vw tech reckons  safety mode tripping in ecu .

[john87]

ok well sounds more likely what you are saying, if the temp sensor fails, the fans will run constantly as a precaution

[blue28]

Yeah  it makes sense ,thought I'd check on here  just in case anybody had a similar problem  before I jumped into buying an ecu  as a according to some reputable testing sites (ecutesting, BBA remann)they are unrepairable as there is no software available ,that is unless someone knows any different ,cheers

[apples12]

Vw mans chatting out of his arse if he's trying to get you to buy a new ECU....

Common problem on the PQ35 platform (mk5 golf, b7 passat, Octavia and a few others) is the cooling fans...

But before you even do this I suggest you get a torch and trace back aaaall the wiring from the fans back to the ECU - it's more common for one of the wires to have become pinched somewhere thus throwing the g83 fault... Veeeeeeeeery unlikely to be your ECU

If your wiring checks out perfectly ( I personally would use a multimeter and a wiring diagram to make sure each point to point connection was good - particularly to and from the g83 sensor and the fan control packs) then I'd look into replacing your fan packs with a used set from a scrappy...if this works - either keep the set from the scrappy if your so inclined - or if your on good terms with the scrappy, return them and purchase yourself a set of brand new ones from VW....


(check wiring at fan pack end - the fan packs are VERY common to go...they'll either run very slow or on full...)

[blue28]

Hi apples,thanks 4 your thoughts, had the wiring bypassed and run it from switch to ecu, still  not cured it then had that checked at a  Indy vw specialist, thought it may be  a fan issue (control module) but told by both they are controlled by ecu directly hence sensor fault showing .would try vw but I'm sure they would refer me back to dealers , cheers

[apples12]

Hi apples,thanks 4 your thoughts, had the wiring bypassed and run it from switch to ecu, still  not cured it then had that checked at a  Indy vw specialist, thought it may be  a fan issue (control module) but told by both they are controlled by ecu directly hence sensor fault showing .would try vw but I'm sure they would refer me back to dealers , cheers

It's the fan packs...

[blue28]

I could understand the problem being the fans if it wasn't showing a sensor g83 fault code ,but both garages are saying its the ecu going into safety mode and that's what is kicking the fans in