FAQ: Anti-Lock Brakes and/or Traction Control Light/Lamp On

problem is, i think the air is in the abs motor. when i shake the little resov on the EBCTM (or w/e it is called) the light goes on and off and the motor makes a noise like it is calibrating. any way to get the air out of that other than bleeding the entire system?

how does the vac thing work? does it attach to the bleeder screw orto the top of the brake resov? i may just get some speed bleeders to make this easier.

at least i'm 90% sure it is just air in the brake system somewhere.will it eventualy make its way to the caliper?

The vac thing works like this:



The hose slips over the bleeder screw and sucks the fluid into a reservoir, which you can pour back into the MC if you want (I always replace with new fluid). It's very fast, and may even pull that bubble through the ABS module. Another thing I like, since you're applying vacuum to the bleeder, when you remove the hose, there's never any spilling of brake fluid - it gets sucked up into the hose.

MAKE SURE you watch the MC level. It will run dry in just a few minutes of applied vacuum. You do not want that!

can someone with a FSM please look up how to purge the abs motor of air? i am 90% sure there is air in my abs motor or on one of the sensors.
When i first turn on the car the abs and trac light are not on, then the abs motor runs a few times (applies braking as it it is trying to calibrate itself), and then the lights come on. this is very annoying because if i try to drive the car, and the motor decides to run while i am touching the brakes, the wheels lock up!
i have bleed the brakes half a dozen times, and i even put speed bleeders on the rear b/c i am so tired of bleeding.
i am pretty sure i will need a tech 2 to cycle the motor, but i'd like to know what the FSM has to say about diagnosing the problem and fixing it.
thanks

That reminds me of when a WSS is going bad. But I'll look next time I'm in my FSM if they explain it.

Both of my lights have been on since I bought the car, but the traction control mysteriously began working this past weekend. Lights still on but TC is functioning.

My traction contol off light goes on after short drive and stays on till ignition turned and car is restated and the same thing happens every time. MOcarGuy@aol.com

Sounds like you need a wheel speed sensor/hub/bearing. You need an ABS code reader to tell you which one though.

Hello,
In my friend's 98 Riviera, the Traction Control light is on at all times and can't be turned off. Is this a common problem? Any ideas what could be causing this?
Thanks,
Mikel

Is the ABS light on as well or just the TC, ?

What has your friend checked so far?

Pull each wheel and look for bad/missing wiring to each wheel hub.

Might be the ABS valving (under the hood, drivers side under the iar box) is frozen from moisture in the brake system.

Might be one or more bad hubs.

Someone with a Tech II scanner (usually a dealer mechanic) can tell you which component(s) is/are bad. Dealer diagnostic should cost 1 hour or less of their posted shop time rate ($65 - $100 dependign on where you are).

Albertj

As Albert said could be wheel speed sensor is bad. Each wheel hub/bearing assembly has one and they are part of the assembly. You cannot replace just the sensor alone, it must be replaced as a whole unit.
That is of course if that's your problem, but bad speed sensors are common or the wiring to them breaks. If a wire is broken or chafed and is not too close to the hub you can cut and solder and put heat shrink over them to protect the repair.
Some independent shops have the diagnostic tools to test ABS systems as well as the dealers. That test will pinpoint the problem to an individual wheel or the the whole ABS control Unit. Either way having it tested with the proper equipment is the only way you will know whats wrong.
Good Luck

If the SES light is on as well it could be a Camshaft Position Sensor code like i have, it's a stretch but still possible.

That's why you need to know what the code is so your not stabbing in the dark and buying parts you don't need.

Thank you guys. Looks like I have some homework to do.

It could be something as simple as an unplugged WSS (wheel speed sensor). That happened to me, I didn't check everything and just replaced the front wheel bearings, although I had them apart at the time, but it probably wasn't necessary yet. The light still didn't clear and I figured out one of the rear wheel speed sensors had broken the clip off the wire, so it worked itself to unplugged. I zip tied the wire home and it's all fixed.

A shop should be able to read the code for you, I had to pay $30 to have the ABS codes read somewhere. The average 'code reader' usually won't read ABS codes.

deekster_caddy wrote:

It could be something as simple as an unplugged WSS (wheel speed sensor). That happened to me, I didn't check everything and just replaced the front wheel bearings, although I had them apart at the time, but it probably wasn't necessary yet. The light still didn't clear and I figured out one of the rear wheel speed sensors had broken the clip off the wire, so it worked itself to unplugged. I zip tied the wire home and it's all fixed.

A shop should be able to read the code for you, I had to pay $30 to have the ABS codes read somewhere. The average 'code reader' usually won't read ABS codes.

Hey Derek how many miles are you getting on a (set of) wheel bearing(s)? I am thinking maybe I should replace mine for maintenance, they are over 100,000 miles old.

Albertj

I was at 130,000 when I thought they were going. It turned out they weren't, though, my issue was all from the rear sensor. In general it seems that 100K - 130K seems to be when they start to go out though, so when I was replacing my transmission last year I did the wheel bearings because it was no extra labor. I also did new control arms w/ ball joints at the same time.

Sometimes mine stays on when i start the car, if i shut it off and restart it, the light will go off.

I have the ABS and Traction off lamps lit.

The code said rear sensor problem on left side so have replaced both hubs. Problem is lamps are still lit!!! do you have to reset the codes or should they clear by them selves?

I tested the rear left (drivers side) sensor at the control unit and a signal is present so it should have cleared the fault.

Thanks in advance..

Nigel

they shoulkd go out by themself.
you can check and clean the connections of the wires. they do get sometimes correded. also add a tip of oil into the connections (not kidding). that will protect them of corrosion.

Thanks . yes i thorght they shold go out by them selves.

I use vasoline in the joints.

Nigel

Nigel,
I would clean those connectors of all Vaseline with an electrical contact cleaner or equivalent.
Get a look at the male and female pins to see if they are tight enough to make contact and use Dielectric grease in the joint instead of Vaseline.
Then inspect the harness further up by moving and twisting it gently. It is not uncommon on these to have a hardened / brittle wire that becomes broken inside the loom.
Can be a real pain to find.
Good Luck

So I'm heading up to the pick-a-part yard today to find a brake control module (EBCM) I've seen computers strewn about the passenger floor of a couple of them. Look like there are about 3 computers in that area of the car.

Any idea if one of those is the EBCM?
.
.

Good to know about the EBCM. Let us know if you are able to fix the problem by replacing it.

My guess is would be if you've replaced 3 of the 4 hubs, and that didn't fix it, might want to replace the 4th one. It's also possible that they told you the wrong hub - it happens. I went to get tires put on the wife's Toyota yesterday. The manager mentioned the "left rear" hub had a slight amount of play and I might want to have it fixed. He pointed to the tech's notes, which said "L/R hub". I questioned, are you sure it's the left rear? He then confirmed with the tech, who said, "No, left AND right". I asked if it was left and right rear, and the tech said, "No, left and right FRONT". So we went from a single hub on the rear to BOTH front hubs.

You may just want to go back to Midas and have them scan with the super-duper again. That's what I would do.

The traction control pumps freeze up if the brake fluid gets too wet. A GM Dealer can activate the pump and run diagnostics with a Tech II scanner or the in-house diagnostic network PCs. Might want to ask the midas folks if they can run the ABS diagnostics to assure you the ABS pump works.

If the pump is bad - odds are one of the 3 Rivs in the boneyard will have a good one - get it there or from Ed Morad. Thereafter if you put fresh fluid into the system and change it out when it gets dark (DOT 3 turns dark when it absorbs too much water) then the ABS motor won't give you problems in the future.

I don't remember anyone else posting about an EBCM going bad. IIRC it's on the firewall in the engine compartment and plainly marked with I think an "Ate" tag.

Albertj