Mitsubishi Repair: 1991 Mitsubishi Galant Tranny issue, throttle position sensor, torque convertor

Question
Hello,  I have a 1991 Mitsu Galant with a 2.0 SOHC engine and a A/T transmission.  I bought the car with a dead tranny so no history behind the car.  I purchased a used tranny from a salvage yard out of a car that burned in the trunk area so again no history behind the replacement tranny.  It had been a recent rebuild, when I do not know, but tranny very clean and it did have a reman torque convertor in it.  After installed in the car it is locked in 3rd gear.  I changed out the valve body from the original tranny with no change.  I then changed the pulse generators from the original tranny again no change.  These were both suggested to me by a guy that rebuilds trannys.  He checked it and said he did not believe it was a internal tranny problem but rather a electrical issue.  I attempted to run the tranny codes last night and I kept getting a code 14 but the best I could figure out from my repair cd's was a code 14 only pertained to 89 and 90 years Galant and 1991 year did not list a code 14 in the troubleshooting section.  I have checked all the wire connections on the tranny for bent pins and broken wires all seem to be good.  I looked also for pinched wires under the tranny mount area (very common problem during assemby I work at the Mitsubishi assembly plant in Normal Illinois and have seen that many times)all wires are good.  Any suggestions on where to go from here?  Thanks.

Answer
Joe,
You're most likely correct to assume this is an eletrical problem, and 90% of the time, the problem does come from a loose or broken harness. I don't have experience with tranny problems on Galants, but I know the early 90's Galants that came out of Normal, IL shared many similarities with the Eclipses.  And from what I know from the Eclipses, the code 14 refers to a faulty TPS.  Fault code 14 may indicate an error in the throttle Position sensor circuit, but it does not necessarily mean the TPS sensor has failed. Testing of all related wiring, connectors and the sensor itself may be required to locate the problem.

But it may be possible the PCM is faulty.  I know Mitsubishi used under rated capacitors in their ECMs for their 89-94 cars, and it's very possible those same caps were used in the PCMs as well.  If you haven't already, pull the PCM and inspect the circuit board for any visual damage, this is the time to do it.  It's possible the previous owner had this problem, but kept running his car in 3rd only; which could be why the tranny was dead when you bought the car.  Hopefully you'll find your problem in something simple like a fraid wire.  But check the PCM to be sure.
Good luck!