As thread title....

Have had 2 flat batterys due to my cooling fan coming on ' when it feels like it ' now in most cases this would be due to a faulty temp sensor, but as there are no fault codes my mechanic thinks there may be a problem in the fusebox.....

Anyway here's my post on first problem

http://www.briskoda.net/forums/topic/255530-is-it-just-a-flat-battey/page__fromsearch__1

What to do....

Edited 23 November, 201213 yr by studmuffin

A failing CTS doesn't always throw a fault code. If you have the old black type CTS I would advise you to change it to the later revised green CTS ( Fit genuine VAG part only) as the black ones are notorious for dying..

The CTS has 2 outputs 1 to the temp gauge & the other to the ECU, so if the ECU side is failing the ECU could think the engine is too hot & it'll keep turning the fans on.

A failing CTS doesn't always throw a fault code. If you have the old black type CTS I would advise you to change it to the later revised green CTS ( Fit genuine VAG part only) as the black ones are notorious for dying..

The CTS has 2 outputs 1 to the temp gauge & the other to the ECU, so if the ECU side is failing the ECU could think the engine is too hot & it'll keep turning the fans on.

Yeah thanks for that, have been told it could be a number of things like control module, bad earth or wiring etc, etc... So would it be a good idea to change the CTS as it is the most obvious and easiest repair ?

Have you had it plugged into VCDS? A lot of generic fault readers & even Snapon diagnostic tools don't recognise all the VAG codes. To be honest your car being on a 57 plate should have the revised green CTS fitted which rarely fail.

Have you had it plugged into VCDS? A lot of generic fault readers & even Snapon diagnostic tools don't recognise all the VAG codes. To be honest your car being on a 57 plate should have the revised green CTS fitted which rarely fail.

Yep, it has been plugged into vagcom with no fault codes...

Was hoping it was going to be a easy fix,

So am now looking for a needle in a haystack again....

This is the second intermittent fault I've had in 5 months, my vRs is very good at going wrong and showing zilch on a laptop...

Edited 23 November, 201213 yr by studmuffin

Check for water ingress in the fan wireing connector

More than likely the fan itself.

ive had 3 flat batterys in 7 days, the 2nd occasion was on a brand new battery 8hrs after it was fitted, ie..new battery fitted at 9am, flat at 6pm when i returned to car, than after 5 days of problem free starting, another flat battery, so its very intermittant....

Get it plugged into VCDS again & have a look in some of the measuring blocks for anything unusual.

Hopefully found the problem, its very damp and dirty under the fusebox, so its going to be cleaned and hopefully cure the problem,

Watch this space......