I have a 1994 GMC Jimmy 4wd and my abs light keeps coming on after a few minutes of driving. I can shut the vehicle off and turn it back on with no abs light, but it will trip again after driving it for a few minutes. At the same time the abs light comes on, the transmission and speedo start acting sporadic. The speedo jumps around and the transmission will either act like it is in neutral, not shift higher than a certain gear, or it feels like the clutch is engaging and disengaging randomly. All of this lead me to believe it was the abs wheel sensors, so i replaced both (front left and front right). This worked for about 10 minutes, then went back to doing the same thing. I had it hooked up to a code reader after that and got one code: 72 trans output speed sensor. This is the sensor located on the back of the transmission which i then replaced. Again, the vehicle was fixed for about 10 minutes and went back to doing the same thing. Now i'm confused at what else it could be?
hi
have you checked out the pcm box it is the black box ontop of the coolant resivore. im not sure just a thought mine is doing similar things but after i shift manually it seems to remember and i can drive normally until i shut it of then back on. best of luck to u
have you checked out the pcm box it is the black box ontop of the coolant resivore. im not sure just a thought mine is doing similar things but after i shift manually it seems to remember and i can drive normally until i shut it of then back on. best of luck to u
Molson02536
New member
Start with the simple and inspect the wire harness for corrosion or any signs of damage causing a short. Replace if there are any signs of damage and keep us posted.
Good luck
Molson02536