Have had trouble off an on for months now with my auto going into limp mode. It won't downshift below 3rd even when you come to a stop and will only go as low as 2nd manually and wil go to 3rd with a clunka s soon as you move the shifter regardless of speed. Have replaced the solenoid in the valve body and the pressure sensor. It use to only do it when towing at freeway speeds now it does it anytime. The only code it would post is gov. solenoid pressure sensor voltage to high. We also installed a resitor in the wire from the PCM to the trans. and that didn't work either. So far all of the remedies have worked to some degree for a while but it always returns. One time I dropped the pan and switched out the new gov solenoid and put back the old one and it went away for a week. What affect could dropping the pan possibly have on this bug if any? Could it be the PCM going bad? My warning light for my airbag has also been coming on at times, could this be PCM related? Any ideas guys? Twogun

 

Ok I had a spare used PCM from the days when I had my lock unlock problem so I switched it out and it didn't go into limp mode but now my ABS and Brake lights are on. It's icy here in spots and the ABS is not working. How is this related to the replacing of the PCM? Twogun

 

try the output shaft speed sensor. This could cause both of the issues you are seeing. Get a scanner on it and read output and tcc speeds. Swapping the sensor is easy, so see if you can find a buddy that has one and swap it to see what happens.

 

The ABS and brake light were not a problem until i changed out the PCM, but when I did, I did not disconnect the batteries. I disconnected them for the night now and also cleaned the terminals on the PCM and will see if I have any issues Sunday. The Air bag light is still coming on and think maybe I picked something up while 4 wheeling accross my snowy corn fields. Will clean out the front Sunday also. Where is the output shaft speed sensor, inside the valve body or outside the trans.?Twogun

 

.....and let me guess. When this occurs if you pull over, shut the engine off, and then re-start it it's ok for a little while.

 

Any codes showing?

 

Yes: If you shut the motor off it will reset. Changed out the PCM and it has worked just fine since Sat. night. Something with the replacement PCM is conflicting with my ABS as the light is on and it does not prevent the brakes from locking up. It is a used one and maybe needs to be reflashed? Was going to put some serious miles on to be sure it was the source of my limp mode issue with the transmission before going to the trouble of reflashing the PCM.Any other Ideas? Twogun