1G '94 Auto Transmission Issues stuck in limp mode

[royal_flush]

Okay, I'm about to pull my hair out. I have a '94 Eclipse GS with an AT. Mine's stuck in limp mode (2nd gear) which I originally assumed was a solenoid (previous owner took it to a shop that said that, but they didn't check wiring).

All four valve body solenoids returned proper spec resistance (~20 ohms for shift, ~3 for pressure reg, and ~13 ohms for damper clutch ctrl). So I moved to wiring and found that between the TCM and the connector for the solenoids right above the transmission had zero continuity whatsoever. Plus, the wires inputting the TCM are a different color than the ones coming out of the connector in the engine bay. So there's gotta be another connector somewhere but I can't for the life of me find it.

Am I even on the right track here?

I've gotten a decent chunk of the way into removing the dashboard totally to try and see about maybe getting all the AC equipment out of the way, but this feel just a little too extreme, so I'm just gonna ask y'all.

Any help at all would be spectacular, thanks.

 

[steve]

The TCUs are as bad as the 1G ECUs with the capacitors leaking. Are you sure your is good? You can get diagnostic information from it. Check the manual for the process.

https://www.dsmtuners.com/threads/1g-1992-1993-dsm-automatic-transmission-factory-service-manual.517373/

 

[royal_flush]

The TCUs are as bad as the 1G ECUs with the capacitors leaking. Are you sure your is good? You can get diagnostic information from it. Check the manual for the process.

https://www.dsmtuners.com/threads/1g-1992-1993-dsm-automatic-transmission-factory-service-manual.517373/

I'm not totally sure the TCU isn't bad, I haven't checked it. I'll look into that too, but it still doesn't explain the distinct lack of continuity in the wiring. Our best guess here is either a failed connector or somehow all four wires are severed somewhere.

Does anyone know off the top of their head if there's a wiring connector for the main entering bundle on the interior of the firewall, behind the dashboard and air handling unit?

 

[royal_flush]

Update:
TCU microprocessor looks fried to me, though second opinions would definitely be welcome. Looks like the distinctive heat bubbling from when the cap dumps the 12V on the 5V wiring that seems to happen a lot to this TCU. Should have been the first thing I checked...

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[steve]

I haven't had any coffee yet this morning but that looks more like the conformal coating they dip the PCB's in to protect them from moisture. When they blow up it's usually a dime sized bubble that often cracks the package and signs of heat.

Do you have a picture of the whole board?

 

[royal_flush]

I haven't had any coffee yet this morning but that looks more like the conformal coating they dip the PCB's in to protect them from moisture. When they blow up it's usually a dime sized bubble that often cracks the package and signs of heat.

Do you have a picture of the whole board?

Yep, on further inspection that night we concluded it was just the non-conductive coating to prevent arcing. I don't have a picture of the whole board right now, but I'll get it later tonight.