I gave my son my 95 Trep and all was good. He drove it for a while and started to have problems. First of all, he would turn the key and not have any gauages. He could flip the key off and on the get them back or if he was in a hurry he would take off without the gauages. BUT the tranmission wouldn't shift out of first gear. He said that sometimes the gauages would come back AND the transmission at the same time. I checked the fuse box and the breaker box under the hood. I checked the wiring as best as I could. I went today and put another BCM into it and no change. The only thing he has done to the car, we installed a new radio. I have checked that wiring 4 times and is OK.

toxic_todd

P.S. We unhooked the battery tring to reset the BMC

 

Many sensors all use the same 5v reference circuit. If that circuit is compramised it can shut down a lot of sensors at once.
The reason the trans and guages are tied together is that without a speed sensor you will have to speedo. The computer won't know how fast the car is moving and then cant shift at the right time - so it goes into a default "limp-in mode" where it will continually be in second gear.

If only the speedo isn't working, replace your speed sensor.
If NO guages work - it could be that 5v circuit... and that could be caused by any sensor on that circuit shorting out.
Or maybe even the I/P - but I don't think that would affect the trans - because the PCM would still get the speed sensor signal.
There are a lot of things it could be.

The diagnostic manual is going to tell you to monitor that 5v circuit - then unplug one sensor at a time to see which one cures the short/open condition. But, if I am wrong, and it has nothing to do with that circuit - this wont' help you.
Best thing would be to take it to a prol.

 

Thanks for the info... It did have an O2 sensor going bad. I'll check that first.

Thanks again,
Todd