1999 Chevy Cavalier Z24 Low Trac light comes on then ETS and ABS are disabled

[Peter D]

OK, here's a puzzler that I can't get figured out. Maybe someone here knows
something. I'll try to list all the facts and cause/effects I see.

Last year, around October, I had a service done on the car. Highly
recommended and good rep shop. They also rotated the tires. The tires are
near new, about 15K on them and still not showing any signs of wear.

On the drive home I noticed the "Low Trac" (Low Traction) light come on,
which I thought was odd because the road was dry. It came on again 2-3 times
and then there was a clicking sound like when the ABS kicks in and the ABS
and ETS (Electronic Traction System) lights came on (means they are
disabled). I'd been driving the car for about 3-4 months and never seen this
happen before. Anyway, I had stopped at a light so I turned the car of and
restarted it ('reboot' if in doubt!) and it didn't happen again on the ride
home so I thought no big deal.

However, for the next 2-3 months at random intervals this sequence would
repeat itself -- Low Trac light comes on 3-4 times in a 1-3 minutes interval
and then the ABS clciks and the ETS and ABS lights come on and are disabled.
Sometimes this happened when I was on the road and the road surface was
suspect. I called the shop and told them it happened right after they
rotated the tires, took it in, but couldn't repeat the problem (totally
random). Then my battery and alternator needed replacing and I noticed that
after that the problem never repeated.

The car went in for an oil change and general winter checkup back in Dec,
and yup, they rotated the tires, and the problem came back. I have
underground parking and if I start my car and a second or two later the Low
Trac light comes on (I'm stationary!) I know that the ABS and ETS will
disable before I can even get outside. I usually turn the car off and
restart before I leave the garage. About 50% of the time this solves the
problem for that trip. It also happens when I turn tightly, especially a
left turn at low speed (like in my parking garage).The problem occurs more
often when it's really cold (it's been -40C lately!) and the car has been
parked outside overnight and now the ETS/ABS will disable without even the
ABS click sound that tells me it's about to disable.

Now, to me this is a problem with a sensor or something on one or more of
the tires. I'm assuming that the "Low Trac" shouldn't come on when you're
stationary on dry ground or moving on dry, clean ground. The problem is that
in these kind of road conditions I like having my ABS and ETS working, but
not knowing if they're working unless I glance at the panel and see the
light is another layer to deal with in a situation. I thought of
disconnecting the battery and seeing if that solves the problem but I don't
know what else that might screw up (if anything). I'd like to go back to the
shop and get it resolved, but I want to know I've done everything I can
before I do that (it's way across the city and I'm so busy I can't give up a
day without my car).

Any ideas? Any suggestions?

[Steve Mackie]

OK, here's a puzzler that I can't get figured out. Maybe someone here
knows something. I'll try to list all the facts and cause/effects I see.

Get the codes read. Remember:

1. Light comes on.
2. Read codes.
3. Test drive.
4. Light comes on.
5. Read codes.
6. Diagnose.
7. Repair.

I'm not sure how fast of a typer you are, but that was a lot of words. Too
many for my to read but I got the gist of it: lights came on and I didn't
notice any DTCs whilst skimming.

Steve