2002 Chevy Cavalier- Trac Off and Check Engine light are on and the car is shifting hard.

Have a scan done

If your speedometer and tach are not working, the car won't shift correctly. The computer needs these inputs in order to know when to shift. Get a new gauge cluster from the salvage yard. I know this is the case for Toyotas. Not a Chevy guy so I'm not 100% sure.

Scan done. Check Engine Code P0502- Vehicle Speed Sensor Circut Low Input. Vechicle speed sensor has already been replaced and it did not fix anything.

Here's my take on it. I'm not an electrical engineer nor do I know how your cars computer system works. Since it's saying low input, does that mean it's not getting enough info due to the fact that your speedo is not functioning? As I said before, this holds true for Toyotas. I would suspect that it would hold true for your vehicle as well. Before I spent a ton of money bringing it to a dealer, I would hit the salvage yard and swap out speedometers. You need one anyway. As far as your TRAC light, when you have the CEL illuminate, that automatically will trigger the TRAC light also. It doesn't mean that there is anything wrong with the TRAC system. I'm not sure how your whole system works, but on some systems the ABS works in conjunction with the VSS. I would check your wheel sensors and see if you have any broken wires. Here's a video: https://www.youtube.com/watch? v=nBqZ6lQ3IVQ I would also change shops. What was doing a tranny flush for $250 going to accomplish with a CEL and a speed sensor code? Nothing, besides screwing you out of $250. Check out the video and see what you think.......

more info: http://www.engine-light-help.com/speed-sensor.html

Check Engine Code P0502- Vehicle Speed Sensor Circut Low Input. VSS (Vechicle speed sensor) has already been replaced, MAP sensor has been replaced, Gauge cluster has been replaced and I have not had any luck. Should I try be replacing the TPS (throtle position sensor) or could something else be causing this??

So what is the car doing as of right now? Still revving high and the tranny is still clunking? I believe the reason that your tranny is clunking is due to putting into drive with very high RPM's. You may have a bad tranny mount which is causing the clunk noise. Remember there will be much more torque when slamming it into gear with a high RPM. Have you tried replacing your Idle Air Control valve?

My car starts up and idles normally, everything fine when I put it into reverse to back out of the driveway. Sometimes there is a loud clunk when I shift into drive but not always. The RPM's are not always running high, only when I shift into gear and take off from a dead stop. When I shift into drive from of park or reverse and begin to take off down the road, the tranny seems like it is not wanting to shift out of first gear, the tach shows very high RPM's (around 4200-4500) and then the car shifts very hard and jerks into the next gear. It seems to only get stuck at running at high RPM's when first taking off from a stop and driving in first gear, once it hard shifts out of first gear the rest of the gears seem to shift ok but are still jerking a little harder than normal. I don't know what else I can do to try and diagnose the cause of the problem

Have you pulled your transmission fluid stick and checked it? You must check transmission fluid with the engine running. Just in case you didn't know. Try cleaning you Mass Air Flow sensor. I have read other posts and they said that after changing out the TPS and cleaning the MAF, they noticed a difference. Also remove your throttle body and clean all of the carbon from the butterfly. Too much carbon may be causing it to not close all the way.

I have an 02 Cavalier. Starts fine, stays running but shifts hard, late shifts and rpms fluctuates. I disconnected the battery to reset the comp. The trac off light and engine light hasn't came back on yet. Ot just shifts jard and have to be at high speed or the rpms have to rise over 3k.

I have been dealing with the same issues with my 03 cav. All started after i changed the entire cooling system because of overheating issues. After changing many sensors, and unnecessary parts, i found that it was a bad wheel sensor (due either to poor connection, junk wires, or just plain old bad sensor). Try finding the wheel sensors, and following the wires...might find your answer there.

I am currently having this same issue. Did you ever get it fixed??

i have a 2003 cav, just randomly after sitting for a few months the speedometer wont show speed, along with wont shift at all. reverse fine, put into drive fine, just wont shift, any ideas?

my 04 cavalier has 285k miles on it, my transmission was fine until i had a flush done on it. i know what the clunk noise is your talking about ive heard it a few times and sometimes it jerks the car around when it shifts but for the most part it works fine id say 85 percent of the time. every so often say if im making a u turn and i want to floor it so approaching traffic dont have to slow down then it will take its sweet ass time gaining speed until the clunk noise is heard and then it goes no problem but i dont know its a mystery problem i have never figured out. i just take my time and dont put myself into situations where i would have to floor it and hope for the best.

ive done a lot of work with the car and i know a pretty good bit about cavaliers so if you have any questions you think i may know the answer to shoot me an email at subroutine c 47 at g ma il.com just take out all the spaces.