[Mikel89us]

you still need a scope to see the switching pattern. Min max will only give you those values. It is impossible to get a correct and acurate pattern without a scope. If the shops you go to test them without a scope (be it on a scan tool or scope) i would stop going there....

[Cobraman1024]

So I finally got rid of the 172 code today.
I figured I'd try the correct 5-speed ECU for my '93 and found one for $25 at a local junkyard. Although the A4LD computer allowed the car to run, I was still going to get the 522, 629 and 566 codes that are A4LD specific.
I put in the 5-speed computer and obviously didn't get the A4LD codes anymore but even after driving for 7 miles, shutting the car off, restarting and driving for another 6 miles, still no 172 code showing up. The final test would be waiting until the car has completely cooled down and restarting and driving it which I'll do later tonight.
On another note, I also solved the airbag light and code 51 (internal fuse open because of internal short)......Opening the airbag diagnostic box showed me that the fuse was perfectly fine. I replaced it with another diagnostic box but that one showed code 34 (drivers airbag low resistance). I replaced it with a third diagnostic box and it was all good, no codes. That diagnostic box was obviously stuck with a false code just like the A4LD ECU.