1999 Pontiac Grand Prix Repair Question
Mileage: 129,000 miles.
Pontiac Grand Prix Engine Problem
Asked by D1985Answer
you need to have engine and trans compatible with your computer. it seems tha tit wold be easier to put all the correct sensors in engine. check tosee if they are all hooked up and scan for codes first. it may be the harness isn't plugged in correctly
TY today i had diagnostics ran on it and kind of figured that out it came up with one code only ... PO502 (low input speed sensor) showed twice one old and the other pending then we looked up the computers and for 97 it was 4T60E for 99 4T65E
So now I'm just stumped on where to go from here is there a way to adapt it where it will get the right voltage to the speed sensor? Will it be as simple as just changing the speed sensor? I'm lost when it comes to this electrical stuff. This is the newest car I've ever owned or worked on. I believe there is a trans shop here that does free diagnostics so im gonna see what their ideas are tomorrow hopefully. Mechanically I think the trans is still good the fluid i drained out was pretty clean. Not alot of metal shavings or any large shavings... there were small pebbles in the pan? lol no idea how that happened but i dont think they ever made it through the filter or thered have been more metal shavings. Changed the filter and put lucas and new trans fluid it shifts right now not hard like b4 but just every now and then it doesnt want to upshift from first until 3.5 rpms when normally it will shift a little past 2. Thats another thing throwin me for a loop why would it get the right voltage and shift when its supposed to sometimes and others not until its at higher rpm?
the 4t60 and 4t65 may not be tht much different like maybe a another clutch or so in it. they did have a 4t65 in 97 just not for the 3.1L so it shouldn't be that much different however after looking at wiring diagram it looks as if the 4t65 has a pressure control solenoid in it which the 4t60 does not. I'm sure a trans guy can figure this out alot better than me as they deal in them all the time.