Hello,

I bought a cheap AUQ(-engine code) ECU from a Skoda Octavia VRS, the ECU is stock acording to the seller. I wanted to try it on my A3 1.8T AUM(-engine code), but of course the new ECU must be paired with the instrument cluster. I managed to retrieve the login codes for both ECUs using Vag-Commander, and followed the steps from the Ross-Tech website for Immo3 ECU-Swapping:

All steps work fine until the final step, when I hit "Test" button the values change to "32000" but I get the message "SYSTEM" "Not OK", in the two upper message boxes from VCDS, instead of car's VIN and immo-id.

Skoda AUQ ECU part number: 06A 906 032 HN
My car's ECU, AUM, part number:06A 906 032 HJ
From what I read, AUQ(180HP) and AUM(150HP) engines are phisically the same. Soft coding-ul is the same in both ECUs and both ECUs are ME7.5

Am I missing something or the Skoda ECU is not compatible with the Audi Instrument Cluster?
Is there a (easy) way to make the new ECU to work on my car?

Any help greatly apreciated!

If the ECU is compatible or not im not 100% sure on that.
Someone else can chime in on that.
However if you get the "system not OK" on a ECU that is compatible here is what you do.

Go into the CANBUS gateway.
Go into coding and even if you keep the same coding, you must clear out what is there and re-type it in.
Press do it, done ok
and then perform the adaptation with the ECU.

otherwise ask adam hes running hn software on hj

I kept reading around this forum(great forum BTW) and got another idea.  Lets say I manage to read the original ECU's 94050 EEPROM and write it on the new ECU, using the argdub's tool...will this bypass the immo? I know I could just disable the immo, but I would prefer to keep it on(not that a 12 years old A3 would be a desirable car for thiefs ).

This is not an urgent issue. My original ECU was remapped two months ago to 190HP(tested on dyno), but I have some doubts regarding the quality of the map and wanted to compare it with the "stock" 180HP and afterwards decide which one to keep.

At this point everything should be fine.
The cluster will not have changed and Since the ECU is a used one even if it did it would not matter.
But when you get system not ok nothing will have adapted/changed.

Clone the eeprom in the ECU and try that.

Will that ECU work in your car? That is still debatable though.

Clone the ECU or Immo off it and test.
Easy peasy..

I managed today to read/write the EEPROM from the AUQ ECU, I plugged it in my car, the immo light goes off , I can crank the engine but is not starting.. When I crank the engine, the ESP light is flashing. I scanned the engine/instrument cluster for errors but no error is found.

So I guess the AUQ ECU is not an easy swap on an AUM engine for the extra 30hp.

Edit: Nevermind what I said. It's working, I didn't found any issue so far.
First try: copied the AUM EEPROM with immo off on AUQ ECU=>not working
Second try: original AUQ EEPROM with immo off=> works perfectly(so far)

I will update if any issue appears.

Thank you to all for the guidance!

My instrument cluster appears to work correctly with the AUQ ECU. So far I didn't noticed any issues in running the car with the AUQ ECU, but tomorrow I will do some more testing.