I've been working to resolve an issue on my Suburban for what seems like months and still unable to locate the issue. It'* a 1999 GMC Suburban K1500 Running a Code P0753 (Shift Solenoid A), However runs and shifts fine through all gears. I've replaced both A & B Solenoids, verified all of the fuses/ECM Connections, Internal Transmission Wiring Harness looks to be in decent shape. Just not sure what what else to look at... Any help is greatly appreciated!

you trace the wires back to the pcm and ohm them out? check for pinched loom?

I have traced back as close to what I can figure out but I'm not exactly sure where it goes into the PCM, One thing I should note is that this transmission was rebuilt recently as well (by AAMCO), because its over the 30 days they wouldn't cover it but the pan was leaking, etc. So when I pulled the pan it appeared that one of the internal wires (brown one) looked to have been pinched in the pan (which would have explained the leaking). However the wire didn't look "bad" and I did my best at testing it with an ohm and seemed to be okay. I would love if I could find a step diagram of how to test from start to finish. Thanks again for the reply!

your trans is a 4l60e by the way, im not sure if i have anything for that. i would certainly be interested in the brown wire. in the trans environment hot, trans fluid, and a ton of vibration all it needs is a little pinch and the rest will vibrate loose

Is that the only code you are getting? A faulty ignition switch can give you that code, but you will have other codes as well. I am surprised your transmission is not defaulting to 3rd gear with that code.

MegaShift 4L60E

you should be able to ohm the pins. make sure you test from the pin to the trans case as a short to ground will mess it up too

As always there is a little "more" to the story. For some reason unknown to me by the previous owner they replaced the 4l60 with a crate 700r4. And yes, it is the only code that I am getting. It'* definitely not in LIMP mode, and if I lead foot it I can feel all 4 gears. Thanks

some how im a little suspicious for the fact the the only thing electric on a 700 is tcc, the rest is traditional style shifting and vacuum and tv cable, etc...

Hmm, possible that the paperwork I have is incorrect? Is there by chance a stamp or something on the trans that I can pull off to verify?

i dont know, i think the pans are the same. the 700 would have a cable to the throttle body. i really think it is a 4l60, a 700 wouldnt be able to be wired to give you the codes you are getting