Hi all,
Diagnostic story
So i had a check engine light come on in this car 01 a6 avant 2.8 ATQ, its a p0103 MAF signal to high. swapped mafs out of another ATQ and a new hitachi form worldpac no change.
I used a lab scope to check the signal wire from MAF to ECU pin 4 on MAF and pin 29 in ecu. when the maf is plugged in and engine running i have constant 3.11v unplug the maf and its 7.5v. either touch or WOT the gas pedal and i get no change in voltage. i removed the MAF signal wire @ 29 pin to ecu and confirmed when engine is running i have a solid 1.5-1.7v (good MAF signal to ECU) at idle and when given gas (MAF sees more air) the voltage does increase like it should, at the pin that is removed from the conn. at ecu. then check voltage of pin 29 in ecu (signal wire FROM MAF AKA an ECU input signal) 7.5v is present while engine is running. I determined this as a ECU failure after checking all powers and grounds at ecu pins, they are ok. The ECU is back feeding this circuit internally, opened up the cover and all looks ok ( cant always visually see the issue on circuit boards) I bought a used ECU from a local junkyard from a 01 VW Passat with 2.8 ATQ with 4 motion correct VIN split and all and the IDENTICAL part number as mine installed in the A6 (3B0 907 551 BS) plugged it in and start the car and the immo doesn't recognize the ECU of coarse but it does start then stall after 2-3 sec (should be a good ECU to at least start the car) but no voltage is being output on this pin of this used ECU. so i assume its definitely a ECU issue.

Said ok tow it to the dealer and have them reprogram the ecu to the car and immo. after being there for 2 days i have gotten the run around with them, first they say its the wrong one and cant do it ( but P# is identical), talked with there parts guy and he confirms its the right one (they cant find me the correct ECU p# new from Audi yet). this am i called and asked what's the issue with programming it they are the same P#'s and they give me a line that they still are unable to program my supplied ECU.

So i am stuck with a car that runs terrible and needs an ECU but they either really cant program it or they don't want to, I'm not sure which one.
I am wondering if there is anyway for me to program this ecu to the car, i already input coding from old one into new one with vcds but i am unable to do the immo function.
Any tips on how to do this?
i have seen videos on removing eeprom chip on the circuit board and swapping them. i am unable to retrieve the PIN required to do this function on vcds. any other ways to do this? any advise would be greatly appreciated.
I have access to vcds, ALLDATA and identifx.


Thanks Nick

 

You probably know that all you need is the SKC to recode with VCDS. You can retrieve the SKC with nefmoto or vag commander or maybe hacking tools. It sounds like you are capable of doing this based on your troubleshooting description.

 

Thanks for the reply,
I can get all the way untill it asks for the PIN/SKC.
I'm just not sure how to obtain it via those programs.
I will search them and see what I can come up with.
thanks

 

those apps are complex and the instructions are written by people familiar with module coding. I never needed mine, so wasn't motivated enough to set up the app. At least you have the VCDS cable, which those apps can use. Once you've downloaded the app, you can extract all the coding and find the SKC in the mass of numbers. The complexity comes when you remap the engine for more performance, like the chip makers do.

Locksmiths may have the software to hack the code and get the SKC for new key coding, so you might try in that direction. Also if you have an Audi/VW tuner shop nearby, one of them might have the ability to dig in and get the SKC, or just have them do it for you.

 

here's a link on vag commander. Somewhat different issue, but should shed some light on your needs.

https://www.audizine.com/forum/showt...-new-key-issue

 

Thanks for the help guys, I bought a handheld scanner called super VAG, that is able to retrieve the PIN/SKC from ecu, cluster and immo. grabbed the pin from old one and used one and able to code the used ecu to the vehicle.
Dealer said both ecu's I provided were no good....
all replies were very helpful,
thanks