ABS Activating During Turns

[spencerb]

Sometimes when I make a nonstopping turn (put on brakes to slow, but not stop, and then letting off the brakes and accelerating as you turn at an intersection), I hear the ABS activate during the turn. At that time my brakes are not applied, and it happens when I turn left or right. It makes the very distinct groan.

This has happened at different intersections without potholes.

I don't get any dash warning lights, but could a wheel speed sensor be failing for example?

[JPDucketts]

could be a sensor going bad, but if you have an AWD Vue you may be hearing the groan of the rear driver module.

[IMkenNY]

If your foot is not on the brake pedal the ABS will not engage even if you have a wheel sensor problem.

If you have AWD I believe you are hearing the RDM engaging.

My 2002 AWD Vue will make an ocassional RDM noise on slow sharp turns.
The rear drive wheels are designed to engage (via the RDM) when the RDM senses the front tires rotate faster then the back(ie. front tires slipping). A slow sharp turn could cause this speed difference.

The newer RDM design allows for a greater speed differential before engagement. This solves most noise complaints but several people have complained about how slow the all wheel drive is to engage.

[spencerb]

Sorry I should have mentioned that it is FWD.

The sound is very distinct and identical to the ABS self-test sound. My foot is not on the brake when it happens. It's intermittant, so diagnosing it will be difficult.

So if the brake isn't applied, the ABS system basically is inactive? So if, for some odd reason, one wheel stops turning and the rest keep going, will ABS activate thinking the wheel is locking? The possibility of a wheel locking without braking is so slim it would have to be a result of a malfunction.

What causes the ABS system to throw a code? I know if the recirculation pump fails the self-test it will illuminate the light. How does the system know if a wheel speed sensor is bad?

[2004NJVue]

[QUOTE=spencerb]Sorry I should have mentioned that it is FWD.
...QUOTE]


You mention its a FWD in your signature section at the end of each post

[Dante]

My vote is wheel speed sensor going out. If it tends to happen only in turns, then maybe it's a loose wire. Take off the front tires and check to make sure no wires are frayed and clean the wheel hubs and everything in there. Could be brake dust causing problems, perhaps? I'm not exactly sure how the wheel speed sensor works. I doubt it is optical. It may be magnetic.

[IMkenNY]

FWD....mystery solved.

I bet your ABS is engaging on slow turns because of a failing wheel speed sensor or a tire is spinning with that 250HP because you also have traction control and the traction control is actually engaging.

The wheel sensor will throw a code when it completely fails to generate pulses.

Do you have the ability to turn off traction control to test this theory (the 4cyl VTI traction control used in 2003/2003 had a button to turn it off)

[spencerb]

I know the traction control did not activate (dash light didn't come on). I don't fly around turns, and I've only noticed the sound in my neighborhood and streets around town. FYI the only way to deactivate traction control is to put it in reverse or low gear.

I would like to know more about the specifics of the ABS system in my VUE. Do all four brakes activate independently based on their respective wheel speed sensor's data? That's my guess.

So the current theory is that a wheel speed sensor is going out, but not to the point of failure. I wonder how the computer knows a sensor has failed? Maybe a permanent or sustained open loop in the sensor is the trigger for the warning light.

Can Saturn test the sensors, such as by comparing speed data from each wheel? My concern now is that it's intermitant, and it will work fine when I take it in. I do need to take it in for this, a sticking window switch, and the window felt that scratched my tint. I live over two hours from my nearest retailer, so I'll have to plan ahead. I also only have 3K left on my warranty. Do you think if I tell them know I'm having a problem, and they find it after warranty, they would cover it?

[ssicarman]

The ABS system will not activate with out the brake pedal down. As in a signal from the brake switch that the pedal is down. I was thinking that it may be the traction control as well but that would not activate the ABS system. It would control wheel spin by reducing engine power. Definately try driving the conditioons with the traction control off to see if there is a difference.

[IMkenNY]

ABS has independent control over each wheel

Saturn can monitor and graph the wheel speed of each wheel with the tech2

Take it in while its still under warranty


I was under the impression when I had the traction control on the FWD 4CYL with the VTI that they did use the ABS to pulse brake the slipping front wheel for traction control and the power would be transfered to other wheel.That system was quite effective.

Did they change it for the honda V6? Below is an article I found on the net for traction control noting both traction control systems:

As marketed by most automakers, but related to ABS, is Traction Control. Traction Control is used to prevent the drive wheels from losing grip when accelerating. Spinning tires during hard acceleration may be dramatic, but it is the slowest way to get to your desired speed. Using the car’s ABS speed sensors at the wheels, the Traction Control computer compares the drive wheel’s speed to the car’s road speed. If there is a loss of grip event during acceleration, there are a number of ways that the Traction Control slows the drive wheels so they can regain grip. The most common method is to use the braking system. When the drive wheels lose grip, the ABS computer can apply the brake to the wheel that has lost grip to slow it down so it can regain grip. Another method for slowing the slipping wheels is to reduce the amount of power applied to them. The computer will electronically modify the amount of fuel entering the engine and/or use the transmission to slow the drive wheels so they can regain grip.

[spencerb]

I'm thinking now that maybe the sound is in the suspension.

I hate weird noises. I guess I just need to turn up my XM louder. :D

[spencerb]

I had the dealer look into this, and they couldn't reproduce the sound but lubed something in the suspension anyway. It still makes this noise, and I'm 99% certain it is the abs. If I brake during a turn, I can hear and feel the vibration in the pedal, and it continues throughout the turn even after I take my foot off the brake.

It doesn't do it all the time, which makes it hard to diagnose.

People have mentioned that the abs will not activate if the brake pedeal is not depressed. I could be wrong, but this does not seem to be the case for me. Is there a way to verify this, and if it is the case, what could be malfunctioning?

The traction exclamation light does not come on when it does this.

The only way to turn off the traction control is to drive in low gear. I guess I could do this around my neighborhood to see what happens. But then again, since it's intermittant, I won't know anything for sure unless it happens with T/C off.

[lightorch]

Here are the specifications if you choose to perform a speed sensor check.
It's the same for all 4 wheels:

(Ambient temperature, in Fahrenheit degrees)
-30F to 40F = 1250 - 1800 Ohms
41F to 110F = 1500 - 2100 Ohms

The wheel sensors are by far the most susceptible to failure.

Think, when did you first notice the problem?

Are they clean?

Are all 4 tires the same size?

An under or over inflated tire can "sometimes" cause problems too.

What about each wire and plug, unseen damage?

Was it after a recent brake job or front end work?

Did you run over something? Was it after service was done on the vehicle?

[Tommy D]

If I brake during a turn, I can hear and feel the vibration in the pedal, and it continues throughout the turn even after I take my foot off the brake.



If the above statement is correct you may be looking at something other than a ABS problem. It is quite possible that it may be a rotor or wheel bearing problem. Good luck

[JPDucketts]

sounds like the RDM to me

[spencerb]

sounds like the RDM to meI don't have a RDM.

[spencerb]

Think, when did you first notice the problem?
Not long after I got it used in July with 26K miles. I have about 40K now.

Are they clean?
Haven't checked.

Are all 4 tires the same size?

An under or over inflated tire can "sometimes" cause problems too.
All four tires are new, put on a couple months ago, and properly inflated.

What about each wire and plug, unseen damage?
Haven't checked.

Was it after a recent brake job or front end work?
It's never had any brake or front end work.

Did you run over something? Was it after service was done on the vehicle?
Nope, but I can't say for what happened during it's previous ownership.

Thanks for the specs on the sensors! I might just get in there and wiggle wires and give it a good checking with my multimeter.

[spencerb]

Oh, and the ABS seems to activate when I'm driving over potholes sometimes, even without braking.

[MY05SilNicRL]

My RL makes some groans as well. I notice it if I'm braking and turning at slow speed and when one front wheel, always the one on the outside of the radius runs over a manhole cover or somthing similar. Also noticed it when backing out of my driveway with brakes applied gently and one front wheel drops from the curb before the other. But thats what the ABS is designed to do, detect a difference in speed of rotation when the brakes are applied. It must be sensing that a wheel is locking up. I wasn't too concerned about it.

[inski]

I bet your brakes are nearly worn out, or a wheel speed sensor.

You need to leave you vehicle at the dealer and have them inspect the brakes (with the wheels off, tell them to give you measurements) and have them drive it around while monitoring the wheel speeds via the Tech2 until your problem happens. Its unsafe to have the ABS kicking on when they aren't suppose to.


I had a Vue in the shop last week with the same problem you have. He came in for tires but I noticed his screwy ABS activation. He's coming back this week for diagnosis. If I remember I'll report my findings.

[spencerb]

Please let me know what you find. I did take it to the dealer under warranty, but they couldn't find anything wrong. I'm out of warranty now, and 2+ hours away from a retailer. So I plan on doing all the work/diagnosing myself as much as possible. My retailer is good about shipping parts to me for a reasonable cost.

[JPDucketts]

i still think its the rdm

[mr_mike]

i still think its the rdm

It's FWD