Immobilizer locked on new ECU, VAG-COM/Ross Tech gurus please help!

Nick101

Boost fiend
Joined
Dec 16, 2008
Messages
212
Reaction score
15
Points
18
Location
Swansea
Fitted my newly acquired stage 2 mapped ECU today, it's off my old car which has been broken.

I know that the Ross site has a guide on how to sort the immob when swapping ECUs between cars, I tried this one first:

Ross-Tech: VAG-COM: Immobilizer 2 ECU Swapping

But the car still starts then cuts out, read codes and it showed the 17978 code.

Im sure the car is the Immo2 system.

my old car was AGU, same as my current, my old one was 97 and this is 99.

The old ecu part number is: 06A 906 018 CJ

The new (mapped) ecu part number is: 06A 906 018 D

Don't think this matters though.

I have re-fitted the original ECU, and the car starts fine.

Can anyone please help? I am desperate to feel the full potential of the KO3s again!

Thanks.
 
If its immo2, you need to unlock the ECU before pairing it. If the ECU is a '97 then the ECU will be IMMO1 though.

What does the immo light on the dashboard do?
 
How do I go about doing that?

Will the mapped ecu be immo 1 and my existing one be immo2 being a 99?

For some reason the immo light on the dash has never worked, old ecu or new.
 
immo light not working is odd.

Perhaps the immo is duff or not programmed, and the old ECU had it bypassed and the bulb removed to stop the flashing light?

Stick the old ECU back in and try starting the car with just the key blade, so theres no immo transponder, and see what happens.
 
I think both ecu's are immo 2. When you refitted the original ecu did you have to program the immobiliser back to that ecu or did it just run?
 
Aragorn - it did strike me as odd why the light was not working, but I thought the same as you, bypassed or something. When I just tried to start it with just the key blade, it started and ran fine.

Ben - when I re-fitted the original ECU back, it fired straight up without the need for vag com.
 
Anyone have any ideas? Is the only way to sort it to code the immobiliser out?
 
Thinking out loud...

if your trying to put immo 2 into immo 3 you will need to turn the immo off or replace the cluster aswell.

I know how to remove the immo, but no experience personally on the petrol models.

Do you have both cars still complete? I may be able to help but im a long trek away.
 
I'm not sure if my current A3 is immo3, pretty sure it's still immo2 being halfway between PFL and FL and AGU engine. So as far as im
aware it's an immo2 ecu going onto an immo2 car.

Unfortunately my old A3 (the one the mapped ecu came off) has long been broken, the one in trying to fit it to is in one piece and working with the original ecu back in.

Shame you are so far away! Is the procedure deferent between derv and petrol models?
 
When I just tried to start it with just the key blade, it started and ran fine.

This is the important bit.

Assuming you just used the metal blade (and not the whole plastic front of the key), and it started, the cars immobiliser is disabled/broken.

Your working ECU will have the IMMO defeated, the new one does not.

You'll either have to get the immo deleted from your new ECU, or fix the cars immobiliser properly.
 
I had a feeling that the existing immo had been disabled, as the light was not working, the existing ecu has been opened before by the looks of it.

Any idea about how I go about removing the immo ffrom my new ecu?
 
Alot of things I am reading to do with this involves finding out and entering a code for the ecu, we found this on vag com, but being immo2 I don't know if this is relevant for me, and we didnt want to start fiddling without knowing what we were doing.

Do I need a code?
 
sned it to someone that knows what they are doing and for a small fee they can remove the imo. Badger 5 or rtech can do it iirc
 
That link looks very in depth, cheers mate.

Found this link on page 1 about disabling the immo, there looks to be a programme in there.

Is my ecu ME7?

if I can't do it myself I will send it off to someone.
 
Your ECU is M3.8 unfortunately, so the 95040 tool wont work AFAIK.

On yours, you'll need an external programmer, and either a SOIC clip or desolder the chip and put it in the programmer.
 
Ahh poo :( so there is no other way than that then?

Looks like I'll be sending it off to someone.
 
Yes, you can refit the new ecu with the correct tools and instructions ( as per your first post) if there is an immo on it, or send it off to be defeated.

Did you use genuine tools? are there any errors present?
 
Have you actually READ the thread?

The functionality of his immobiliser is completely unknown. Given the existing ECU has immo defeat, and the immo light has been removed (not an easy feat given its an SMD LED!) it seems very likely that its broken. In what way its broken is anyones guess, but it has to be pretty broken for someone to goto the effort of removing the LED and de-immoing the ECU wouldnt you think?

Ofcourse, it might just need setup from scratch with proper tools, new transponders etc. Or there could be faulty parts or wiring that could be difficult to track down. You simply dont know.

So you have simple approach A; de-immo the new ECU and leave everything else as it is, or you have complex and expensive approach B, involving lots of time spent figuring out what exactly is wrong with the immobiliser by someone who has all the shiney expensive tools, followed no doubt by component replacement and recoding everything.

Your obviously touting for work, or are you going to visit him and fix it for free?
 
Have you actually READ the thread?

The functionality of his immobiliser is completely unknown. Given the existing ECU has immo defeat, and the immo light has been removed (not an easy feat given its an SMD LED!) it seems very likely that its broken. In what way its broken is anyones guess, but it has to be pretty broken for someone to goto the effort of removing the LED and de-immoing the ECU wouldnt you think?

Ofcourse, it might just need setup from scratch with proper tools, new transponders etc. Or there could be faulty parts or wiring that could be difficult to track down. You simply dont know.

So you have simple approach A; de-immo the new ECU and leave everything else as it is, or you have complex and expensive approach B, involving lots of time spent figuring out what exactly is wrong with the immobiliser by someone who has all the shiney expensive tools, followed no doubt by component replacement and recoding everything.

Your obviously touting for work, or are you going to visit him and fix it for free?

Would you prefer to visit him and fix it for free yourself or something? You sound upset that im offering help were i can...

I dont see any vcds logs for a start. nor mvb results. nor a correctly adapted attempt to fit the ecu.
Whilst im not an expert myself, and every car is different, there would be nothing to stop me passing by en route elsewhere to have a look and help diagnose better. I also have a shed full of second hand clusters and ecus, new transponders and all the (shiney expensive) tools to get it running right.

Certainly wouldnt be free, but I have yet to hear a single complaint about my prices, and given that i was in bristol saturday, glasgow sunday and surrey yesterday, theres a good bet ill end up only a short trip away from the op at some point soon.

Nothing wrong with the immo defeat approach, just as long as its not broadcast all over the internet fr opportunists.
 
Thanks for the help folks, I have found someone who I can post it to and get it removed and returned in 48 hours.

i will report back when done.