hello, im fairly new to the 2.7t engine, so hopefully some one can assist. i baught a 2000 audi s4 6spd not to long ago. i immediately upgraded the cat bak,intake,and suspention, along with the install of a boost gauge and turbo timer. car ran geat! now i have installed and GIAC chipped ecu. i baught the ecu off ebay, the ecu match my stock ecu exactly, the car ran amazing couldnt belive the power gain. a day later the car sputtered and then stalled on me wile i was driving. and then would not restart just kept turning over. first thing i did was put the stock ecu back in. now the car starts and runs fine! is this a common problem with chipped ecus? is this a fixable problem? thanx, justin

 

GIAC solders an encryption board in the ECU. open the ECU and check if the chip/socket is still in the right place.

 

okay i did that and the solder is all intact everything looks good......

 

if you have a vag-com, plug the bad ecu in and check if you are able to connect to it.

 

keep us posted on the chip/ if there are anymore problems Interested in getting one but scared to blow turbos

 

okay i have tried to connect my obdII scanner up and it tells me system not compatible. do i need a special scanner?

 

don't know what obd2 scanner you are using. does the scanner work with the good ecu?
what's the bosch number of that ecu? 0261-?

 

the number on the ecu is 8D0 907 551 A as long as this number is the same as my stock one the ecu should have worked right?

 

that's not the bosch number, the number starts with 0261.......

 

Correct... but there is no guarantee that the flashed ECU has the "551 A" code.

As mentioned and to know for sure, VAG needs to communicate with it in order to confirm.

Perhaps post a good pic of the circuit board and note any board numbers.