2001 Saturn SC2 Auto Trans

My son drove my Saturn, and came back reporting that the speedomater had stopped working, and the chech engine light had come on. I drove it, and the speedometer worked but the C/E light was on. Two days later the light went out, and nothing else happened. Two months later after running the car through a flooded road, the transmission started slipping, and shifting violently, and the speedometer stopped working, and the C/E light came on. I pulled over turned the car off, and restarted it. The speedometer works, but the C/E light is still on. I think that this is an electronically contolled tranny, but what’s up with this? Do I have a loose connection, bad solenoid, or is the computer going crazy? Advice please.

That CEL (check engine light) is just a kid in class waving her hand trying to get you attention because she has the answer. You need to have the codes read. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code not just their translation into English and post it back here. It likely will have a format like P1234.

Yes your transmission is a computer controlled transmission. The absence of the Vehicle Speed Snesor (VSS) speedometer signel would cause the transmission to shift hard, if not go into the limp home mode, as the computer does not know the output shaft speed and cannot monitor the clutch slippage. It is strange that the signel comes and goes. It might be a wire or connector problem although the VSS sensor could be intermittant. You will have to get the power train computer scanned to verify the code that is being set and have the technician check the VSS and the wiring going to the computer.

Let us know what you find.

OK, I went to Advanced Auto, and the code for the fault was P0500 (speed sensor). You were both absolutely right! Advanced does not carry this part.
I have not checked with NAPA, but regardless…can I change this myself or will I have to take it somewhere? Also what if the problem is a loose connection not the sensor??(I do think it is the sensor because the first indication of this problem was that the car used to not want to downshift when you took your foot off the gas, and started braking).
Thanks! Bill