I was with the car today at a friend's shop today to try to figure out why my GTA was running so crappily when the engine was cold instead of just throw money at new parts (TPS, MAP, CTS, etc).

I plugged in his Snap-on Solus, ran through the menus, entered the info, etc, turned the car on and the Solus had a com error with the ECM. I tried a few things, had Rick (the shop owner) try, bla bla bla. No luck. We whipped out their old scanner, a Snap-on MT2500 and ran into the same problem.

I spent the next several hours tracing wires, checking for open circuits (ie a break in the wires that run front he ECM to the ALDA port), checking to make sure that every wire was in the correct place. Everything looked fine on the car. I finally did the paper clip thing and got a code 12. Unfortunately, the paper clip trick won't let you see what various sensors are outputting, which is the whole reason for trying to get the scanner to work.

The ECM is a GM rebuild. Is it possible that it’s from another car? I tried running it as an 87, 88, and an 89. I tried running the car as a 305 TPI instead of the 350.

Any ideas?

 

My prom isn't on the Thirdgen FAQ.

I have no idea what #'s it's refrencing on it's table, but none of mine are on there.

The chip is a Delco AKXZ3294. It has these other numbers/letters on the sticker - 16064300, 27C128, D5012AC, U7460045X

The two other chips have the following #'s on them. First chip: 16055375 - 8747. Second chip: 16055376-8742.

I'm going to post in the prom board to see if I can get any info on what I have.

Any ideas as to why I can't pull codes are welcome.

 

I have the same problem with another scanner. I get connection error. Did not tried the paperclip jumper to see if I get the 12. I know it worked in the past.
I had running with the inlet temperature sensor disconected (under the plenum) and did not set any engine code
May be a loose ground connection somewhere or bad ecm? car ran reasonably well before.