ABS Failure warning
08-30-2004, 12:12 PM
#1
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ABS Failure warning
Just doing errands Saturday with my son and turning slowly into a parking lot (to avoid scrapping of course) the ABS light comes on and the dash says ABS failure warning. Stayed on after turning car off and on and then went out on its own driving home. I was going to go out on a country road and slam on the brakes to see if the ABS would activate but then didn't have to. Hope it's just a fluke... damn I love driving this car!
08-30-2004, 12:25 PM
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Ski - did you wash your car? Did you dry the brakes after washing? The most common cause of the ABS warning is brakes that stick - rust between the pads and the rotor. This happens with PCCB too. If you had to use some power to "unstick" the brakes it triggers and ABS fault. It goes away never to return and all is well. Could this explain what you saw? Note to avoid this, dry your brakes after washing. Get up to some reasonable speed (30 mph) then apply the brakes lightly once you have applied the brakes put your foot on the gas and drive with the brakes on for about 30 seconds. That heats the brakes up enough to dry any water. Note, brakes first then gas else e-gas will cut the power to the engine.
Regards
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08-30-2004, 12:31 PM
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It has been mentioned in other threads if you happen to get one rear wheel to spin faster than the other (as you go crab through a driveway and one wheel drops off the edge of the curb while accelerating) it can also fault. It took a number of stop and restarts to reset (this is also in the other threads). This happened to me a few weeks ago without much effort.
08-30-2004, 12:37 PM
#4
I had the same thing happen when I very slowly took a turn to avoid scraping recently and felt the inside front tire lift off the ground for about 2 seconds. Since that wheel wasn't turning while the others were, it tripped the ABS light. The light stayed on until I shut off the ignition. It's never come on again. I'm sure that's exactly what happened to you too.
I wasn't too concerned since I had to get my old C2 "smoged" before selling it last month. They changed the emission test here in Cali now and part of it is done with the car going a certain speed on rollers. It tripped the ABS light since the front wheels weren't turning like the back ones. The mechanic told me the light would go out when the system reset itself. He was right, it turned off on the drive home. Nothing to worry about.
I wasn't too concerned since I had to get my old C2 "smoged" before selling it last month. They changed the emission test here in Cali now and part of it is done with the car going a certain speed on rollers. It tripped the ABS light since the front wheels weren't turning like the back ones. The mechanic told me the light would go out when the system reset itself. He was right, it turned off on the drive home. Nothing to worry about.
08-30-2004, 04:39 PM
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Speaking of ABS, does anyone else feel like ABS kicks in too early on the track. It feels like to comes on way before lock up and lengthens my stopping distance. The Pagid pads helped a little but I think there is a lot more braking force available that the computer is not letting me get to.
08-30-2004, 05:38 PM
#6
Jgerken,
I totally agree!...I find that mine come on even on the street far too early.
This sounds crazy, but the stopping power on my range rover feels much more powerful.
With the GT3 you have to apply a lot of pedal force, BUT when you do the abs kicks in.
I am not confident with these brakes whatsoever.
I totally agree!...I find that mine come on even on the street far too early.
This sounds crazy, but the stopping power on my range rover feels much more powerful.
With the GT3 you have to apply a lot of pedal force, BUT when you do the abs kicks in.
I am not confident with these brakes whatsoever.
08-30-2004, 05:47 PM
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Guys,
ABS is invoked when a wheel stops rotating with respect to the other wheels on the car. I also find that the ABS on the GT models allows you a little more lock up than some others I've used. To get ABS to come on you must lock up one or more wheels. If it possible that you are getting on the brakes too hard and getting pre-mature lock up? The other thing which affects ABS is the grip of the tires. An R compound tire will brake a lot harder before triggering ABS than a street tire. A racing slick is simply amazing in this regard.
In a Range Rover, strong braking results in considerable nose dive as the front suspension compresses. This will give you the impression that you are slowing down fast when in fact you aren't slowing as much as you think. The GT3 does not dive anywhere near as much and might fool you into thinking you are not stopping as fast. Is it possible that you're being mislead?
A 911 wants you to brake gently at first so as to transfer some weight up front and widen the tire contact patch, then you can brake a lot harder without locking up a wheel. Have you tried this?
regards,
ABS is invoked when a wheel stops rotating with respect to the other wheels on the car. I also find that the ABS on the GT models allows you a little more lock up than some others I've used. To get ABS to come on you must lock up one or more wheels. If it possible that you are getting on the brakes too hard and getting pre-mature lock up? The other thing which affects ABS is the grip of the tires. An R compound tire will brake a lot harder before triggering ABS than a street tire. A racing slick is simply amazing in this regard.
In a Range Rover, strong braking results in considerable nose dive as the front suspension compresses. This will give you the impression that you are slowing down fast when in fact you aren't slowing as much as you think. The GT3 does not dive anywhere near as much and might fool you into thinking you are not stopping as fast. Is it possible that you're being mislead?
A 911 wants you to brake gently at first so as to transfer some weight up front and widen the tire contact patch, then you can brake a lot harder without locking up a wheel. Have you tried this?
regards,
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08-30-2004, 07:06 PM
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Bob,
Are you sure that the ABS is triggered only when a wheel absolutuely locks up or is it when the computer senses a certain amount of difference in rotional speed? I was under the impression that ABS kicked in just before lock up.
From Bosch's web site,
"Rotational-speed sensors continuously monitor each wheel. As soon as incipient lock-up is detected at a wheel, ABS temporarily reduces the braking pressure at the wheel in question to such a degree that lock-up is prevented."
To me, incipient lock-up means that the speed of rotation of one wheel is dropping relative to the others, but it hasn't stopped yet. If this is the case, then there may be some degree of braking effectiveness lost if the computer's interpretation of incipient lock-up occurs at a lesser difference of rotational speed than you would be able to attain through threshold braking.
Are you sure that the ABS is triggered only when a wheel absolutuely locks up or is it when the computer senses a certain amount of difference in rotional speed? I was under the impression that ABS kicked in just before lock up.
From Bosch's web site,
"Rotational-speed sensors continuously monitor each wheel. As soon as incipient lock-up is detected at a wheel, ABS temporarily reduces the braking pressure at the wheel in question to such a degree that lock-up is prevented."
To me, incipient lock-up means that the speed of rotation of one wheel is dropping relative to the others, but it hasn't stopped yet. If this is the case, then there may be some degree of braking effectiveness lost if the computer's interpretation of incipient lock-up occurs at a lesser difference of rotational speed than you would be able to attain through threshold braking.
08-30-2004, 07:16 PM
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JG - Your statement is correct. I should have said "incipient" lock up. My simplistic statement was just that "simplistic". The ABS controller does measure wheel rotation and compare it to the others (that part was correct). hat's why lofting a wheel can cause an ABS warning light, same with a wheel that's dragging due to a stuck pad/rotor.
Still, I am puzzled since I find the braking on the GT3 to be quite good. I can threshold brake like crazy without invoking ABS. I only get ABS when the surface is uneven or has wet patches and then I am glad to have it
I wonder if a wheel alignment problem could explain what you feel? I would expect my car with neg 2.5 camber in front to bemore likely to invoke ABS than a car with a street alignment. OTOH many GT3's have been delivered with messed up alignement ...
Still, I am puzzled since I find the braking on the GT3 to be quite good. I can threshold brake like crazy without invoking ABS. I only get ABS when the surface is uneven or has wet patches and then I am glad to have it
I wonder if a wheel alignment problem could explain what you feel? I would expect my car with neg 2.5 camber in front to bemore likely to invoke ABS than a car with a street alignment. OTOH many GT3's have been delivered with messed up alignement ...
08-30-2004, 07:44 PM
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Bob,
I'm running the same alignment and ride height specs as on the GT3 that is doing very well in SCCA racing this season. We are not running quite as radical negative camber as you, but I'm getting very even tire temps and the car feels very neutral and extremely planted. I have Pagid R19's and R compound Corsas. Since both of us feel that there is more braking available that we are getting, perhaps it is an alignment issue.
I'm running the same alignment and ride height specs as on the GT3 that is doing very well in SCCA racing this season. We are not running quite as radical negative camber as you, but I'm getting very even tire temps and the car feels very neutral and extremely planted. I have Pagid R19's and R compound Corsas. Since both of us feel that there is more braking available that we are getting, perhaps it is an alignment issue.
08-31-2004, 12:02 AM
#11
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I hadn't washed the car but was turning slowly over a bump and bet that one wheel was probably off the ground as mentioned above. Good idea...
08-31-2004, 12:14 AM
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JG - I can't think of anything else. Negative camber is not the best thing for braking mind you but I wonder if one wheel was more negative than the other, would it tend to lock up first? If trail braking (uh-oh dangerous topic!) one wheel would tend to lock first (unloaded side) and trigger ABS. Are the discs badly cracked? I am grasping at straws here ...
Onelast thought, we are on different tracks, perhaps it is a heating issue?
) one wheel would tend to lock first (unloaded side) and trigger ABS. Are the discs badly cracked? I am grasping at straws here ...Onelast thought, we are on different tracks, perhaps it is a heating issue?
