MK5 Golf GTI

All Things Mk5 => Mk5 General Area => Topic started by: Multicrazy on August 06, 2023, 06:56:39 pm

Title: Ecu swap car dies and throttle does nothing
Post by: Multicrazy on August 06, 2023, 06:56:39 pm

Hello everyone so today my car just doesn’t want to start it cranks but won’t start, also the obd port doesn’t seem to want to connect. So first I checked the fuse box and the obd fuse was blown I replaced it but still it won’t connect.

So I decided to leave it to a mechanic to diagnose the issue but then I noticed under car I saw this was broken or it’s unplugged?

It’s under the driver side (right hand drive) just next to the timing belt. Does anyone know what this sensor is?


(https://i.postimg.cc/Bv8CTb62/IMG-6862.png) (https://postimg.cc/bGhb8z1v)

Edit : so there was water in the ecu and it was damaged. I replaced the ecu with another one and got it reprogrammed the car starts now but dies after like 10 seconds and the throttle does nothing. Could it also be a faulty ecu or faultly coded ecu? The codes I am getting are P0657, P0444, P2294 and there is no immobilizer active message.

Could it need adaptation mine is a manual 2008 gti. I’m just stuck and hopeless one problem is leading to another. Any help would be appreciated :(

Title: Re: Ecu swap car dies and throttle does nothing
Post by: pudding on August 11, 2023, 09:08:28 pm

No idea what the picture is!

Sounds like the immobiliser wasn't disabled. It's all you can do with used ECUs as it's hard coded to the donor car's VIN.  VAG were doing firmware lock downs waaaaaay before Apple  :grin:

 If you want to restore the factory immobiliser, the only way to do it is with a brand new 'virgin' ECU from the dealer and have them download the software onto it from VW's servers.

There's a few ebay sellers that sell used ECUs with the immobiliser already removed, which are usually plug and play.  If not, the engine map on it is likely wrong.  Obviously with such an ECU, the car can easily be nicked, and you'll have to tell the insurance.