03 sierra denali trans elect problem?

[tallicazx6]

I had a problem with my battery draining over night and I finally got a chance to try to figure it out. I put an ammeter on the battery and one by one pulled each fuse until I figured out which circuit was causing the problem. I think I traced it to my ignition switch, so I replaced that. But, now I have transmission problems, it will not shift and I have codes of P0740 P0785 P1860, all transmission codes. Is it possible that I caused this by pulling fuses and turning the ignition on, maybe messing up a computer in the process? I tried clearing the codes with my code reader, but they come right back. I am currently trying leaving my battery disconnected overnight and seeing if that might clear the problem.
I had zero trans problems before my testing with pulling the fuses.

[davester]

I would go with "it's possible, but highly unlikely" (that you damaged one/some of the computers as part of removing/inserting fuses).

 

Perhaps all the fuses weren't reinstalled correctly (or a fuse blew), or there was a problem with how you installed the replacement ignition switch.

[tallicazx6]

This problem showed up BEFORE I replaced the ignition switch, sorry I should have clarified that. I left the battery unhooked overnight and tried again just now, still no luck.

[davester]

I would go with treating them as being genuine codes indicating one or more problems, and going through the diagnostic procedures for each of the codes, starting with the lowest number, to figure out what's wrong.

[tallicazx6]

It ended up being a blown fuse for the transmission controller, all good now!!