Ill preface this with the fact that I went through a transmission intercooler failure.

CEL P0751.
I've replaced:
*the solenoiaolenoids
*Trans filter
*Oil
*TPS

I can select the gears (3,1-2) and they work fine. 1-2 down shifts... A little late but it does.

Where I'm at now.

Yesterday I proved the TCM plug at the TCM and also checked power at the TCM wires when energized. Here is what I found.

Ohms:
Pin 1&2 (Input speed sensor Ground & signal -704 Ohms SHOULD BE 400 Oms

Pin 6&7 (CCD BUS -&+) 60.50hms S HOULD BE 60 Ohms

Voltage checks:
Cav 6 2.39Vdc (CCD BUS -) SHOULD BE 2.51

Cav 7 2.42 Vdc (CCD BUS +) SHOLD BE 2.49

TCM ENERGIZED:
Pins 25 & 26 Batt Voltage when it should be there

PIN 12 (SOLENOID A) .012Vdc WHEN KEY ON AND IN D. [It should be energized to call for 1st gear.]

The only solenoid energized throughout all gear selections is solenoid B

Cav 18 (R) energized when gear selected meaning the signal is being received by the TCM

Cav 22 (D) energized when gear selected meaning the signal is being received by the TCM

IN CONCLUSION

It looks like I may have a bad speed sensor (ohms and voltage are a little off)

Possibly a bad TCM? because it's receiving the signals, but it's not turning around and energizing the components it should be.

Can anyone deduce something else going on here?

 

The input speed sensor won't cause your issue, and I've never seen one fail. P0751 points to a solenoid A issue. Did you check the resistance across the solenoids (11-15 ohms)? Either the solenoid or the wiring is shorted to ground or the driver in the TCM is blown, or both.

 

yes, I actually ended up ordering 3 sets of solenoids and tested ohms and engagement.

The odd thing is that the TC lockup soleoid wouldn't click twice the shift solenoids. it would only click once, and then it wouldn't click again unitl after a little time passed. I that normal? Thats why I ended buying 3 sets but they all behaved the same...

Also when I check them at the TCM harness they Ohm out at 15.

 

The TC solenoid is different. It closes when activated versus the shift solenoids that open.