ECU - where is it?

[8vgti]

Where is the ECU hidden in the car - is it under the bonnet or somewhere inside the car?

Cheers

[carl]

its under the plastic where the wipers are.

[8vgti]

thanks for that Carl. If I have a faulty ECU, what would I need to get a replacement from a breakers....do the codes just have to match from the one in my car to the one I get and would it simply be plug and play?

[EvilScotsman]

You can't do that matey.

The in-built VAG engine immobiliser is coded to your key and another ECU will refuse to start the car cos the key would be unrecognised. You would have to get the ECU re-coded by a dealership to match your key or take all locks and the ignition barrel and smart-key to go wi the replacement ECU from the breakers.

No scrapyard ecu swaps wi vw im afraid 

[8vgti]

oh dear I hadnt thought of that  Lets hope its not the ECU then....will have to wait for the stealership to do their diagnostic check as my local garage could not identify the cause of the the non-start/poor running problem (thats why its now at the dealer). The fault codes that were coming up were for parts that my motor doesnt even have, so it looked like the ecu was scrambled.

Any idea how much it would cost to have an ECU re-coded to match my key???

[EvilScotsman]

Dont know mate but someone here will soon post the amount.

I just had a thought. You could get the key to go with the ecu from the breaker (they might insist you take the ignition barrel too) but dont change it - get another key made where they can do vw keys (wi a code reader like mister minit keycutting or summat) and get them to cut a copy if your own key but wi the second key's transponder code. Then throw the one from the breakers in a drawer and hey presto - ecu swap! Only the new key will start the car but the original will still open the doors anyway - they will have the same blade but different transponder codes!

[Len]

A new ECU with key will cost £200 - £250.

Recode a second hand ECU to your car/key £80 inc p+p. I was quoted that about 3 years ago when I had my problems.

8vgti - mate before you get your fault codes checked again, change the ECU relay! A faulty relay doesnt show up in a fault codes check.
Also disconnect the battery for 15 mins. This will do a reset and should delete all the other faults. Or stop them showing up again.

[8vgti]

Cheers for the responses.

Could I get the an ecu and key from the breakers and then just swap the chip from within the key with mine?

Len - I have tried everything mate and the ecu relay was the first thing I tried as I have had that problem before (see the early post on the huge post about golfs cutting out and oil light flashing!!!).

The story is....car was running fine, left it for 4 days and then when I came to use it, it just wouldnt start. It turns over, has plenty of spark and fuel is cutting through. Changed leads and dizzy cap as I have never done them, and tried all the usual relays. Took it to local garage and no faults came up on diagnostic. They had it for a week and tried various things and managed to get it running. Then when they were driving it was running really rough and you could only build up speed very gradually or it would die if put under any load. They turned it off and now all it does it turn over.

So I thought the only option to at least get a diagnosis and get the car back on the road (buses and trains arent good!!) would be to take it to the stealers. They cant look at it until tomorrow so will wait and see. MAy not be ecu I am just investigating options in case it is.

Len - where did you look at getting the ecu for £80??

[Len]

That was to reprogramme.
They had already done a full check on mine that cost me £55. And found nothing wrong with it!
Bear in mind that this was 3 years ago and they may not do that service any longer!

www.aptelectronics.com

[Len]

Further thoughts - if you are getting spark at the plugs and fuel my guess its not the ECU.
More likely timing. Or perhaps a sensor. Dunno if Golfs are the same but I had similar on my 405 Mi16 - turned out to be the water temp sensor.