MK5 GTI - Dead ECU

[harley1990]

Hi Forum!

It's looking like my ECU has packed it in. Car wasn't starting after it was washed, so I had a mobile mechanic come out earlier in the week. VAGCOM was failing to connect to the computer, so we pulled it out, and it was leaking out water. Took off the top cover, gave it a shake, and water was still coming out. Gave it quite a shake, and then we tried plugging it back in and it started up! I paid to get it professionally dried out (trying to confirm what exactly they did), but upon getting it back and connecting it, it's not starting once again. Seems to well and truly be dead.

So, next step I guess is a new ECU? I've tried to do some research, but am a little stuck. To my understanding, I need to get a new ECU, with the same part number, install this, get it towed to Volkswagen who will then code the instrument cluster to the ECU?

Anyone got any tips? I'm dreading how much this will all cost in the end.

[h100vw]

That's the score mate. There's been a few dead MK5s in the past, the swimming lesson won't have helped. You need the same part number as the one that's in.

If you can find one on ebay, you could have the immobiliser defeated and it will run fine.

Google MED9 immo defeat.

A new ECU fitted and working at VW will be circa $3k I reckon.

[harley1990]

Hi Mate,

Thanks for the reply. The one i've got is a 1K0 907 115 F and I've found one that is a 1K0 907 115 J. Assuming that's not going to work?

Did some research on the immobiliser defeat, and the impression I get is I need to be able to get the codes out of my old ECU via VAG-COM? Unfortunately, the ECU won't even connect to it.

[h100vw]

Hi Mate,

Thanks for the reply. The one i've got is a 1K0 907 115 F and I've found one that is a 1K0 907 115 J. Assuming that's not going to work?

Did some research on the immobiliser defeat, and the impression I get is I need to be able to get the codes out of my old ECU via VAG-COM? Unfortunately, the ECU won't even connect to it.

A 115F will def work I doubt if VW could tell you about the 115J as they wouldn't have ever done that job. I don't know what the immo is on an MED9 but the ME7 you can just desolder the immo chip and fit it in the new ECU.

No idea if the MED 9 is the same.

Gavin

[Umai Naa!!]

VW dealer will tall you what ECU will fit off the VIN.

J may be a superscession of F.

[harley1990]

Great! I'll give them a call tomorrow.

If it is a match, and I can't do an immobiliser defeat, am I correct in understanding that they can just do something 'relatively' easily to match it up with my dash cluster?

Thanks for your help guys!

[Umai Naa!!]

Yeah, they'll have to adapt it to your cluster.

Not much involved in that.

[Lucas_R]

MK5 GTI - Dead ECU

Same thing (dead ECU in Mk5 GTI) happened about a year ago to my friend. It just died all of a sudden.

Cost him $2,200 for a new ECU through VW and approx $1,200 for coding/labour etc. Was just under $3,500 all up.

[Umai Naa!!]

Oh well, at least he'll save himself $1100 in diagnostic time.

[harley1990]

So, some good news. The J supersedes the F, so it'll work. Have ordered it for $350 and will swap it over. Volkswagen have quoted me $250 for the coding.

Lucky it's nowhere close to $3,500!

[Fatherless One]

Good news, this kind of operation has always worried me (money wise), glad to see it can be done relatively cheaply.

[harley1990]

Yeah, I was dreading it. I think provided you can find one online that matches it's not too bad, otherwise you're a bit out of luck!

[parso_rex]

Good news, this kind of operation has always worried me (money wise), glad to see it can be done relatively cheaply.

Actually you might not be out of it yet. From what I've gathered VW/Audi here can only re-image a virgin ECU which means the one your ordering can't be used until you have someone make the ECU appear in a virgin state - and that's not that easy.
What we usually do is 'clone' the existing ECU when it can be read, This involves reading all three memory locations within the ECU and basically transplanting the data into the same areas on the replacement ECU. This also works across a range of ECUs withing the same hardware family -2007 GTI ECUs can be used in Golf R's for example (Thats VW doing that one BTW on a replacement 'virginised' ECU as a warranty job).
I'm doing exactly this on a TDI mkV atm actually. The 'dead' ECU needs to be removed from the car opened up and then read via BDM and then the reverse occurs with the replacement ECU. The big thing to note though is that the ECU processor and other memory areas have to be alive enough in oreder to be read. If the eeprom which contain the Vin and immo data is damaged or has corrupt data then pretty much you'll be screwed and you'll need to go hunting for Virgins and be friendly with your VW dealership

Cheers

Mark

[harley1990]

Oh, i was under the impression it could be. I struggled to get someone at Volskwagen who knew about it, but ended up speaking to a guy who knew a bit about it.

To my understanding, the reason that anyone except Volkswagen can't do it, is because the codes are held by VW. They access the codes via their system, and then reflash it.

I'll have to try make some more calls and try get to the bottom of it, because it's booked in to go to VW early next week.

[harley1990]

Update, called VW today and they said that they should be able to recode a second hand ECU, even if it's been in another car before. They said that that's not to say some other issue could come up when they try to do it, but yes they can recode them.

Think i'll call another VW dealership to confirm