Hey Guys,

I was wondering if ECU upgrades can affect the OBD on our cars. I did a unitronic 91+ stage 1 upgrade about a year ago but never really did any other diagnostics on my car since. Recently; I tried a regular crafstman OBDII scanner on my car, as well as using my mechanics snap-on / wireless OBDII scanner, and neither one could establish communication. There was always some error code.

Has anyone had issues like this? I don't know if it's something else but the ecu upgrade is the only thing i could think of that may have caused the issue. I want to try other alternatives before i take it to the dealer for a $125 diagnostic. Who know if the VAG-COM itself will actually work as opposed to the other methods. I also experienced the TCM getting wet (which is why i need to check the codes - cause i think my car is in limp mode) but I don't think communication with the main computer would have anything to do with the TCM right?

Any help would be appreciated.

2000 A6 4.2L