Trac Off Light after repairing Radiator Fan on 2002 Cavalier


Asked by Apr 27, 2013 at 10:49 PM about the 2002 Chevrolet Cavalier Sedan FWD

Question type: Maintenance & Repair

Here's the sequence of events so you know exactly what happened:

About 2 years ago I had an issue with the engine getting hot and figured out eventually
that the fan relay was bad.  Replaced it, all has been well.

Recently I had discovered I was leaking some coolant.  First thought was to check
reservoir.  That's fine.  Then I replaced relay, that didn't help.  Finally I did a test on
voltage throughout entire line from relay, etc.  Voltage was getting to fan, but fan
wasn't turning on.  I replaced the fan, and it works just fine.

HOWEVER, once I started the car after I replaced the fan, I drove a little bit, and the
TRAC OFF light came on as well as the check engine.  The car died.  After a little
while, i was able to restart it, and both lights were off.  Then the TRAC OFF light came
on again, and the car was shifting really hard.  Winding up to 4k in 1st, and then
slamming into second, etc.  It would go on and off intermittently.

I eventually figured out how to reset the computer by disconnecting the + terminal and
holding the brake for 15 seconds.  That clears all lights, however after about 20
seconds of driving, the TRAC OFF light keeps coming on.  As soon as the fan relay
kicked in, it turns the light on.

What could be causing this?  I ordered a computer code reader, but obviously I have a
general idea of where the problem lies.  Wondering if anyone else knew/had this

8 Answers


sounds like current is back feeding somewhere or wrong fan relay causing such! pull relay and see if ok. if need be feed fan direct key on hot 12 volts and let run.


It's your throttle position sensor, get the codes read at a local auto zone. The transmissions shift point depends on throttle position. The further you press down on the pedal the higher rpms the trans shifts and its a faster stiffer shift. A bad sensor will cause the transmission to shift harder at higger rpms because the transmission thinks the pedal is being pressed down further. It sounds stupid but trust me, it happened to my wife's 01sunfire.

2 people found this helpful.

John. My Mom's 02 Cavalier is shifting abnormal and her trac off light is on. Where should she take it to see if its the throttle position sensor? How much will that part cost to have replaced?

6 people found this helpful.

Is the check engine light on also? Take it to AutoZone or advanced auto and have them scan it for codes. Do you know how turn a wrench? You could attempt to fix it If you want. Just 2 screws hold it in.

3 people found this helpful.

I won't be with her when she stops to have Auto Zone look at it. the sensor is held in by 2 screws?

1 people found this helpful.

It's the ECT sensor. I finally figured it out. It was the first thing I checked and replaced but after a month of trying everything, I took It back and replaced it with the Delco model as opposed To the valucraft, and it worked. Problem solved. It was worth it to pay the extra 5 bucks. You'll need to replace the sensor which just screws into the upper radiator pipe and the harness which is two wires, yellow and black. Since the sensor was faulty, it made the car think it was going to overheat and shut down power to everything which is why the trans goes into its low power mode. I didn't think a brand new sensor would be faulty so I kept overlooking it, but in the end, that's what it was.

3 people found this helpful.

Thank you Michael and John. I have forward this info to my Mom so she has it when she goes into Auto Zone :)

Was this problem ever solved? If so, what was the problem? My car is doing the exact same thing.

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