ratprod

Hello all,

New here, but not to auto forums. Anyway, I recently bought a 92 accord ex with 196k miles and a transmission issue for $300. I thought it would be an easy TCU change fix, but no.

The issue:

Before: The D4 light was always on solid and the transmission would start in 3rd if I put it in D4. It would never shift to 4th. I could start in 2nd if I shifted to either 1 or 2. No 1st gear either. Then I could manually shift it to 3rd for the duration of driving; no matter what speed, it would never up or down shift. No codes when I jump the diagnostic plug.

Now: I plugged in a good numbers matching TCU and reset the ecu. Now the D4 light is out, but the shift interlock won't release. I can only get it into gear using the key in release hole method. Once in gear, the D4 light never comes on even when in D4. All other lights still work. And I still only have 2nd and 3rd gear that I have to manually shift between. Once I had 1st and 2nd, but then I shut the car off and restarted it and ever since it's been 2 and 3.

I installed a new TPS tonight that didn't help. What should I do to fix this pile. I can't afford to throw parts at it since I lost my job and bought this so I can park my gas hog truck and drop insurance on it. I'm trying to be thrifty.

I plan to clean all the solenoids since I have plenty of time to tear into this.

ratprod

Update... I reset the ecu again with the new TCU plugged in and got a different result. The shift interlock still doesn't unlock so I used a key. The D4 light was on solid, then flashing in no particular pattern. Fast and slow, no way to tell what code because it just kept flashing wildly. Then when I put it in D4 it started in 1st, shifted through second and 3rd before I was going 25 mph, then downshifted to 2nd and that's the only gear I have now. I can't even manually shift to 3rd anymore.

I had to unplug the new TCU and drive home without one so I could use 3rd gear and not blow up.