Hello!New to this website!What I have is a 98 Tahoe.With a p0758 I can not seem to eliminate.I have replaced the pcm with latest program.Replace the solenoid the internal wiring harness.Ran a new wire from the trans to the computure.For the yellow/black wire.Still no getting rid of the p0758.Just wondering if anyone else had seen this problem?Thankyou for any help!

 

Forgot!The ignition switch always has battery voltage on it.It never drops out so the ignition switch is not the problem.Thanks for looking!

 

Welcome to the forum. Have you measured the resistance across the 2-3 shift solenoid? Just take the electrical connector off the transmission and then measure the resistance across terminal E (gets ignition voltage through PNK wire) and terminal B (PCM-supplied switched ground over YEL/BLK wire). If the resistance is zero or infinite, there's your problem. The resistance should be ~30Ω but compare it against the resistance between terminal E and terminal A (LT GRN wire for the 1-2 shift solenoid).

 

I ran a new wire for the yellow and black wire.My resistance is the same fore both solenoids.Also ran a amps test both are the same.Believe its some thing telling the computure some thing wrong.Also have checked from the ignition switch.Voltage is correct 11.90 key on and 13.90 while running.Also have supplied fuse twenty with didifferent supply voltage.

 

So, it's not the positive side, no voltage fluctuations while driving? Then, maybe it's the ground reference side. The PCM grounds the solenoid to actuate it which means the PCM itself has to be grounded good. There's more than one ground wire from the PCM but they all end up in the same grounding point and ultimately back to the battery negative terminal. Have you looked into that?