This is my second post about my ABS problem.
At low speed my abs seems to pulse and come on even when the road conditions
are perfect and their is no loss of traction whatever.
The abs sensors are approx. $200.00 Canadian and I have been warned that I
would possibly have to replace the backing plate through which they are
I have to find the one that is creating the problem. Does anyone have any
suggestions on doing this? If I disconnect the sensor at the closest
connector will it show a failure on one wheel but still operate the others?
Any advice is appreciated in this matter as I want to get it resolved while
I am swapping rotors and pads as I also seem to have a slightly warped
Thanks for your help in this matter,
There is a TSB on this. I quote:
Brakes - Antilock Brake Activation at Low Speeds
Bulletin No.: 02-05-25-006A
Date: December, 2002
Subject: Antilock Brake (ABS) Activation At Low Speeds
(Clean Wheel Speed Sensor Mounting Surface)
1999-2000 Cadillac Escalade
1995-1999 Chevrolet Silverado (Old Style)
1995-2000 Chevrolet Suburban, Tahoe (Old Style)
1995-2003 Chevrolet Astro Van, Blazer, S10
1995-1999 GMC Sierra (Old Style)
1995-2000 GMC Yukon, Yukon XL (Old Style)
1995-2001 GMC Envoy, Jimmy
1995-2003 GMC Safari Van, Sonoma
1995-2001 Oldsmobile Bravada
This bulletin is being revised to change model information. Please
discard Corporate Bulletin Number 02-05-25-006 (Section 05 - Brakes).
Some customers may comment on ABS activation at low speeds usually
below 8 km/h (5 mph). Upon investigation, the technician will find no
The cause of this condition may be an increased air gap between the
wheel speed sensor and the hub reluctor ring due to rust and debris
built up on the sensor mounting surface.
Measure AC voltage and clean wheel speed sensor mounting surfaces.
1. Raise the vehicle on a hoist.
2. Disconnect both the front wheel speed sensor harness
3. Place a DVM across the terminals of each sensor connector.
4. Rotate the wheel with hand speed and measure the ACmV's. The
reading should be at least 350 ACmV's.
5. If the reading is between 200 and 350 ACmV's, remove the
wheel, caliper and rotor in order to gain access to the speed
6. Remove the wheel speed sensor and plug the hole to prevent
debris from falling into the hub during service.
7. Clean the speed sensor mounting surface on the hub to remove
rust and corrosion.
Important: Make sure that the sensor sits flat on the hub. If
the sensor flange is distorted, replace the sensor.
8. Apply a thin layer of bearing grease to the surface prior to
9. Install either the original sensor or a new one in the hub and
secure the sensor. Ensure that the sensor is seated flush
against the hub.
10. Install the rotor, the caliper and the wheel.
11. Place the DVM across the sensor terminals and recheck the
voltage while rotating the wheel by hand. The voltage should
now read a least 350 ACmV's.
Don't ascribe to stupidity what can be adequately explained by ignorance.
I've got a 99 jimmy, i've had no problems, only problem I have is the ABS
activating when trying to stop at a sandy intersection after a snow, I dont
get stopped. Thats why I popped the hood, got into the power box and yanked
the fuse. Now I have no more worries or ABS.
From my experience, and others I have talked with about ABS, it doesn't work
for squat on ice, sand, or a combination of the two. Wet and dry roads is
about the only place they seem to work as they are supposed to.
I have stopped 50+ feet sooner than ABS equipped domestic and import
cars and trucks of various years wit a Dunlop GT Qualifier tired '74 Cutlass
on icy roads.
I don't believe in ABS or trust it... I am with Adam...pull the fuse!
Interesting story to back that up...
An older dude in the neighborhood that me and a friend worked for back
in high school decided he was going to teach us how to *really* drive.
One day while we were going down a 4-lane he stated that, if it came
down to it, one should be able to slam the brakes and cut the wheel,
slide sideways through a break in the median, and come out into
oncoming traffic having executed a 180 on dry concrete. Not that you'd
necessarily need to, but more or less just to demonstrate control of
one's own vehicle. We laughed...That was a bad mistake, and at 45mph,
he proceeded to prove his point...in a high-top Ford conversion van.
Needless to say, the guy really knew how to handle his vehicle and
depended entirely on being able to predictably lock up and unlock the
brakes when needed to do controlled sliding and skidding.
A couple of years later he came home all freaked out. He said he'd
almost ate it in a wreck. While trying to do his usual thing to get
out of harm's way, the ABS kicked in and prevented him from sliding.
He had no ability to control the vehicle because it simply didn't react
I guess it just goes to prove that it all comes down to the driver, and
their knowledge of the handling characteristics of their vehicle.
Same experience my self, I've always owned a vehicle without ABS and now we
got this 99 Jimmy, and it has 4 wheel abs I DONT like it and if I ever buy a
vehicle with it again it will ALWAYS be disabled.... Like I've said before I
like having control of my vehicle with my foot, not some undereducated
We had an '06 Cobalt in December for a rental car, it had ABS and it was the
same way with that car, if you came to an intersection with a little sand or
gravels on it from the snow trucks, or even salt, they kicked in and caused
you to run the stop sign.
"Shades" <shades_1970(at)netins(dot)net> wrote in message
Lets face it...ABS was developed for those people who are clueless
about opperating a motor vehicle. i for one know that if my truck is
sliding and nothing happens when i steer the wheel it is most likely
because the wheels are not turning. cars are funny that way, wheels are
funny that way... they need to be 'rolling' in order to controle the
The ABS in my 93 Buick Park Ave worked good even in the Snow. The ABS
in my 98 Buick Century sucks.
Last winter a inch of fresh powder on the ground. I have a green light
approaching a intersection at 35 MPH (in a 55 zone). Some idiot runs the
light and stops in the middle of the intersection. I applied the brakes,
Low-Trac light, vehicle sliding. I left off, drop from OD to 2nd gear.
Re-apply brakes lightly, causes vehicle to slide. I start applying the
park brake (4 notches) and drop to first Gear. I stopped 5 feet from the
passengers side door of the car sitting in the middle of the
intersection. I still have a green light (and legal right of way).
The guy behind me wasn't so lucky. He slid his Mazda in to the ditch
trying to steer while braking.
Any time Im on slick roads (rain, sand, snow, ect) and I apply the
brakes I get the Low-Trac light. The brakes modulate, and the braking
distance is increased. Releasing the peddle and re-applying with in 4
seconds does not do much good.
Basically it comes down to a piss-poor system design.
I have had the ABS pulsing brake problem at low speed (5 mph & less) 3
Twice on the left front (2000 Z-71 4x4 Silverado) & 1 time on RH
Prob was the wheel speed sensor gone bad... $62 ea US GM Parts
Dealer fixed it under the 6 year GMPP warranty all 3 times....
Prob is you lose your low speed braking at Stop signs & in Gas
Not a good feeling. All is fine now... but I expect another ABS
sensor purchase in a couple years....
I know the feel of the problem... Pulsing on dry pavement under
low speed braking AND no brakes (auto brake release at low speed
A chevy or GM dealer can easily spot the 'which side problem' by doing
a test drive with the GM computer plugged in... The computer
reads both the speed sensor output voltage as the wheel spins....
I have a 2000 Silverado with this problem, but I received a "Recall Notice"
for this problem about 2 months ago. The recall only covers owners that live
in high salt or corrosion areas. I guess if you buy a truck in the South and
move North your on your own.
I refuse to buy any vehicle with computerized brakes, shocks, etc...
don't like cruise control, rain "sensing" wipers, individual "climate"
control, or any of that junk. Just something to make the dealerships
more cash with useless repairs. Don't even like AC, took it off my '86
Silverado... I've got electric windows, so I control the "air" without
even leaning over in the seat.
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