Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
When you supplied the ground, did it start? Did the 5v Ref come Back?
As soon as the Run/Crank Relay energizes, the PCM should ground pin 59 to power up the PWR/TRN relay !!!
Also when you supplied that ground did the check engine lamp illuminate?
PS. i just re-read the whole post>>>>>I am not Paul Danner the proprietor of this site, I'm a member just like you!
But yes, his videos would be a lot to take in lol!!!!!!!
I want to see your check engine light come back, but it quite possible the inputs for Park/Neutral from the TCM aren't being met, you said you heard clicking, there MIGHT be something shorted to voltage, because the input for the Park/neutral is a high side Resistor (B+) in the PCM that is pulled to ground by the TCM. I'm not sure of the logic or there are other factors at play, but Pin 1 of the PCM's X1 connector has to be pulled to ground. I don't see how this messes up the PCM to turn on the PWR/TRN relay, but it very well could.
My gameplan was to get your check engine light back KEY-ON, that has to happen for it to crank. So I decided to look at the starting diagram to see what inputs the PCM wants to see.
The check engine lamp did not come on nor did it attempt to crank. I’ve been thinking the neutral switch is the problem. When I turn the key on there is immediately a switch that clicks in the transmission and a constant beep not like an alarm or chime or a rhythmic beep just a constant non stop beep until the key is turned off or I pull the transmission ignition fuse or the run crank relay. May the tcm isn’t grounding and a solenoid is stuck trying to open or something? I appreciate all your help. Also I didn’t think to check the 5 volt ref but when I supplied ground to the voltage on yellow wire pin 59 dropped to .17 I think it was.
MYC, yes the alarm icon turns off. My key fob works as normal. I can set the alarm off with the fob or with the door handle. And the prnd does function I put it in neutral and pushed it last night to be sure
MYC, yes the alarm icon turns off. My key fob works as normal. I can set the alarm off with the fob or with the door handle. And the prnd does function I put it in neutral and pushed it last night to be sure
MYC, yes the alarm icon turns off. My key fob works as normal. I can set the alarm off with the fob or with the door handle. And the prnd does function I put it in neutral and pushed it last night to be sure
MYC, yes the alarm icon turns off. My key fob works as normal. I can set the alarm off with the fob or with the door handle. And the prnd does function I put it in neutral and pushed it last night to be sure
MYC, yes the alarm icon turns off. My key fob works as normal. I can set the alarm off with the fob or with the door handle. And the prnd does function I put it in neutral and pushed it last night to be sure
Ok that is good the security light goes out, I would think the PCM is not grounding the PWR/TRN relay because it sees something on the Transmission Control Module Side.
Here's a bunch of diagrams:
Be very careful to read the Pin assignments carefully, some of these diagrams cover different engine configurations. There is a lot of diagrams here, I would suggest you look at the Symbol Schematic to familiarize yourself, so you know that a High Side mean B+ and Low Side means Ground.
When you see a Pull-up Resistor >>>When the other end of it is disconnected the voltage should remain High
EG look at the TCM PNP diagram, if you disconnect the PNP all the pins in the TCM 29,46,23 and 39 should be B+ with the Key on
The Pull Down resistor thus would remain low to ground when the opposite end of what it controls is unplugged.
Kudos to GM for letting us know the internal circuitry design.
If the PRNDL lit up and showed you its in neutral that's good too
I think your on the right track about the transmission, something is shorted
So if you look at the starting diagram where the P/N is in the PCM you'll see a Pull-up resistor and it is PIN 1 of the X1 connector, this means that if you disconnect at the TCM with the key on there should be 12 volts present on the Orange wire with a Black tracer. When conditions are correct and everything is working properly the TCM pulls this voltage down to ground. That is what the PCM wants to "see" to start the vehicle, then I think the PCM Grounds the PWR/TRN relay.
