ECU error - need help diagnosing

[flapmio]

Hi,

I've recently purchased a 2006 (56) Audi A3 S-Line 2.0 TFSI.
A few weeks ago it died after heavy rain when my son was driving. He thought he saw the battery light flash on and so got a mate to put a battery booster but it wouldn't start. Luckily a mechanic was passing by and put his computer on it and cleared a load of errors. He said it looks like it has been stage 1 re-mapped. He thouht maybe the card had been filled with diesel, but we confirmed only petrol.
He managed to start it and we got it home and left it for a day. After that it drove fine.

Then a day or 2 later we started to get the engine light come on and when connected to computer we got error code "P0441" - Evaporative Emission System Incorrect Purge Flow.
I bought a Bosch breather purge valve and got it fitted. The error then went away and car drove again for a week.
Then took the car on a 400mile round trip last week and had it washed.
While driving the engine cut out and the battery light came one. Tried to start it in 'D' mode then remembered and put it in 'P' mode and and car started back up.
Got home with no issue. Left it overnight, drve in morning then came back. Tried to start it again after 2 hours and got "ECU" error flash up and "Brakes" flashing up. Engine turns but won't start.
Connected to computer and cleared all errors.
The errors attached are permanent.
I have checked the battery is being charged by the alternator and checked for water in fuse box in engine and it's all dry. No fuses have blown.

Wondering anybody has any experience to save me a long investigation & money waste on where the issue would be exactly?

Thanks

 

[palmgrooves]

Electricity doesn't like water, looks like your issues surface when car gets wet . Inspect fuse box for water ingress / corrosion.
Remove plastic cowling below windscreen and check your ECU or the cables aren't swimming in puddle of water

 

[flapmio]

Electricity doesn't like water, looks like your issues surface when car gets wet . Inspect fuse box for water ingress / corrosion.
Remove plastic cowling below windscreen and check your ECU or the cables aren't swimming in puddle of water

I'll try that

 

[NHN]

I'd also check the ground points front of passenger in the bay for any corrosion, as said water is getting into something, could even be hitting the box connector or mechatronic seals, but I'm leaning towards relay build up that a Dremel will clean back to metal or ground point.

 

[flapmio]

FYI - one guy I talked to said check some brake sensor under the cam-shaft because of the ESP/brake error?

 

[NHN]

You've got multiple errors, which leads to a common issue, ground point or relay would be my 1st check.

Which brake sensor as your age of car has esp yaw sensor under drivers seat & then abs module in bay under & behind battery unless it's an 3.2 with battery in boot & wheel sensors, not sure I agree but hey check everything.

 

[flapmio]

If the problem is water in ECU bay then why is that happening and how can I prevent it from happening again?

 

[NHN]

Well naturally find where the issue is which will determine how to resolve it, it maybe a seal or something coincidental, hands dirty job mate, we can't guide until you find it.

 

[flapmio]

Hi, so double checked and saw the plastic cover seems to have "popped up" where it meets the windscreen (possibly due to heat?) and there's a crack in the middle. So most likely water has got in there. I popped it back down.
However my regular mechanic (who doesn't want to touch it) is adamant it's not an ecu issue?

 

[NHN]

That's the screen trim it's highly unlikely to cause water to get in there as it's fairly well sealed by itself tbh, the connectors all have seals, each pin has a seal, the ECU is sealed shut, it's bear on impossible to get water in there, but there's always a chance but I doubt it's that.

 

[flapmio]

Need a mobile specialist in Berkshire/West London area

 

[flapmio]

UPDATE: So managed to get ECU out and confirmed that it's water damaged. Need to get a new one. To replace do the VAG number & Bosch part number have to be an exact match?

 

[palmgrooves]

UPDATE: So managed to get ECU out and confirmed that it's water damaged. Need to get a new one. To replace do the VAG number & Bosch part number have to be an exact match?

Damn that sucks. Yes ideally you want the same pn ECU. SW version shoudl be close to yours as well. Many modules will likely have to be coded, enabled/disabled anyway (eg. If you get ECU from manual car it'll have to be coded for auto etc.)

 

[flapmio]

Damn that sucks. Yes ideally you want the same pn ECU. SW version shoudl be close to yours as well. Many modules will likely have to be coded, enabled/disabled anyway (eg. If you get ECU from manual car it'll have to be coded for auto etc.)

Thanks buddy. Managed to find one last night on Ebay with exact same VAG No & Bosch part number. Got it ordered.
What programming, if any, will be needed to get it working?

 

[palmgrooves]

The car the replacement ECU came from may have had different options than yours.
Eg. Auto trans vs. Manual, fwd vs. quattro etc.

Yes there's a chance it'll be plug and play but more likely not. You'll need someone with vcds to do it for you. It's not a DIY job unless you know what to change in the coding. It has to be vcds or proper workshop diagnostic tool capable of deep dive into the coding, you won't change this with the small cheap or bluetooth readers

 

[flapmio]

The car the replacement ECU came from may have had different options than yours.
Eg. Auto trans vs. Manual, fwd vs. quattro etc.

Yes there's a chance it'll be plug and play but more likely not. You'll need someone with vcds to do it for you. It's not a DIY job unless you know what to change in the coding. It has to be vcds or proper workshop diagnostic tool capable of deep dive into the coding, you won't change this with the small cheap or bluetooth readers

Yeah, looks like it's from a manual. Mine is Auto.
Cool, will find someone to re-program it then...

 

[flapmio]

UPDATE: So the programmer said he would just copy my old ECUs data onto the new ECU and if it's all good the car should start. Tried that but then had an issue with the throttle body and mechanic suggested a new battery as the old one was a cheapy one because Delphi wouldn't go further than the throttle body error .
Got the new throttle body and battery fitted, and Delphi getting more readings.
Unfortunately they are mainly to do with "01314 - ECU" again

Now I am being recommended to get an "ECU key kit" - guess that is new immobiliser etc.

I just want to check if anybody knows where I can get a good plug and play ECU? I want to give that a try as have had enough and am about £400 into trying to get the car running.