1993 Pontiac Transport 6 cyl Front Wheel Drive Automatic 165000 miles
I have an elderly Trans Sport which repeatedly shows DTC 39 and locks me out of 4th and 5th gear until the car is stopped, ignition turned off, and then restarted. Particularly when the car is asked to climb an extended grade and most especially when the engine and tranny are nice and warm. I can restore normal operation by clearing all the DTC codes with a scanner (allows me to get use of 4th and sometimes 5th gear). Is this a tough fix? How do I replace the TCC solenoid on my vehicle if it is the TCC solenoid?
I also get code 31 (PRNDL fault) (which I think is the ignition switch, to be replaced in a few days) and code 21 (TPS voltage out of range). Are these two related - can a flaky ignition switch cause a code 21?