Traction control, ABS goes out at times....stumped

**01 SS Vert** · 05-29-2009, 02:06 PM

Issue:
Tracion Control Light, ABS Light, and 'BRAKE' light come on sometimes while driving. When this occurs, I loose ABS and traction control even when I don't want to.

Sometimes it comes on, sometimes it does not. Sometimes when it does come on, and I turn off the car for a few minutes, the dash lights go away and the systems return to normal.

What I found:
I figured it has to be rear end wiring related issue since I'm losing both TC and the e-'brake' light comes on at the same time. I currently under the car and I don't see any loose conections, sensors, or cut wires.

Since the way the lights pop up on the dash, I assumed it was a cut/loose wire, but everything looks ok.

All the wiring from the rear end seems to plug into the sheetmetal under the back seat behind the driver; from there I loose it and can't see where it goes. Under the hood, everything looks ok.

ANY IDEAS? This issue is really getting on my nerves. The car is up in the air right now....any suggestions would be great. I've already locked up the tires b/c the ABS was off and I'm concerned this could become a safety issue sooner or later.

Thanks!

**ls1forlife** · 05-29-2009, 02:18 PM

it sounds like a wheel speed sensor. but im not sure about the E brake light...you can test the wheel speed sensors resistance..then you can cancel that out..

**01 SS Vert** · 05-29-2009, 02:32 PM

Originally Posted by ls1forlife

it sounds like a wheel speed sensor. but im not sure about the E brake light...you can test the wheel speed sensors resistance..then you can cancel that out..

Could you point me in the direction/write up on how to test these? Thanks!

**Cutlass** · 05-29-2009, 04:51 PM

All 3 light are related and will come on for a failed WSS. You need to have the ABS codes read at a shop and that will tell you which sensor to replace. It is most likely a front sensor.

**ls1forlife** · 05-29-2009, 06:47 PM

he is a master tech so i would trust him. but you can get is by measuring the resistance with a ohms meter. One plug should come from each wheel, just measure it with the wheel still, and then spin it, the resistance should change. It could be a bad brake computer(ebcm). Vettes do that exact same thing...my guess would be scan it.

**Hi-Po** · 05-29-2009, 06:49 PM

Wheel Speed Sensor more then likely.

Stock wheels and tires?

Shot in the dark, is your brake light in the 'middle' burned out?

**Cutlass** · 05-30-2009, 04:42 AM

If you wanna just measure all the WSS's, then post the results here and I'll let you know if they are in spec or not.

**01 SS Vert** · 05-30-2009, 07:10 AM

Thanks guys! I'll test them late tonight or tomorrow. I'm doing yard work and then going on the lake today - so odds are tomorrow.

I left the car lifted in the air, so I should be able to do this in a reasonable amount of time.

Does the key/ignition need to be in the 'on' position for me to test this?

**Cutlass** · 05-30-2009, 01:00 PM

nope. Just unplug each sensor and test the resistance.

**01 SS Vert** · 05-31-2009, 02:00 PM

Voltmeter ohms settting at 200K

Front Driver Side:
@ sensor 1.1
@ wire plug in 94.1/98.6 (two different #s, swapped red and black around during test)

Front Passender side
@ sensor 1.1
@ w plug in 94.1/98.6

Rear Driver Side:
@ sensor 3.0
@ wire plug in 94.3/98.8

Rear Passender side
@ sensor 3.0
@ wire plug in 94.4/98.9

Conclusion - the rears are the same; the fronts are also the same; but the fronts are not the same readings as the rear. I did the rear first, and when I did the first front one, and got '1.1' vs. '3.0', I figured that was my issue....however both fronts read '1.1' so I'm STILL stumped.

Now I have ANOTHER issue. The front wire plugs will not clip back into the sensor. I tried squeezing the plastic clips together to make a tighter fit, but I'm having no luck. The wire plug will just slip out of the sensor no matter how hard I try and push it in. The rears went in fine. As of right now, I can not plug them back in so, I'm afraid I can't drive it until it's fixed.

I'm so fed up with this crap.

Any help is greatly appreciated!

**cammed goat** · 05-31-2009, 02:04 PM

Did the front clips break?

**01 SS Vert** · 05-31-2009, 02:32 PM

Originally Posted by cammed goat

Did the front clips break?

Nope. They are still attached - but I can't get them to clamp around the sensor tab that holds the two in place.

**cammed goat** · 05-31-2009, 02:40 PM

You "may" have to get some zip-ties to wrap around the sensors and hold them together for the time being.

**ls1forlife** · 05-31-2009, 03:04 PM

im not sure you understand what to do. so if you dont. this is what you do.

measure the resistance with the wheel not moving from the sensor, not the harness.

next. move the wheel and make sure the resistance is changing.(measure from the sensor aswell)

you should see a good change in resistance while the wheel moves

**Cutlass** · 05-31-2009, 03:17 PM

front sensors definitely measure ok. I'm not as familar with this style rear sensor and can't find any good info on it, but since they measure the same I suspect they are ok. Basically this is just a static test, so apparently when these are in motion one isn't reading correctly. The next step is to take it to a shop to have the codes read to see which one is acting up.
You can drive the car with the sensors unplugged if you need to. Just make sure they are clear of moving parts. Are you plugging them in the correct way or backwards possiblly? Or maybe the connector seal is hanging up and giving you trouble. You could try removing the seal to see if it plugs in. Or you could lube the seal with WD40 or something simular to see if it slips in better.

**01 SS Vert** · 05-31-2009, 07:00 PM

Thanks for the tips guys. I'll work on it tomorrow night after work. I had a brain fart for not testing it w/ the wheel in motion.

**01 SS Vert** · 06-01-2009, 05:37 PM

Only was able to check one so far.....spinning the rotor by hand (guessing a very slow speed in reality), it would bounce both above, and below 3.0. I saw as low as 2.88 and as high as 3.1X for the driver side rear.

What kind of values should I expect?

**01 SS Vert** · 06-01-2009, 06:43 PM

I just checked the passenger rear side, and the #s were consistant with the other rear side. Thus, I'm guessing it's one of the front ones right now.

Wish I had an obd2 scanner right now. I should have scanned it again before I got it up in the air.

**ls1forlife** · 06-02-2009, 11:16 AM

you can scan it at autozone with a scan tool for free? or take it to a place with a gm computer for almost nothing. they can tell you exactly what it is in minutes.