why does my left front break suddenly grab while driving?
once a week while driving at 20 mph or 60 mph my front left break will
suddenly grab and release. this sets off the active handling light.
this is scarey!!! the local GM dealer sees nothing at al wrong with
the brakes. obviously, this is a most serious question. this could cause
a deadly accident. thank you very much.
The only thing that can cause this if your not touching the brakes is the ABS control unit itself. If you know how you can disconnect the module and see if the problem goes away, doing this will give you standard bakes, so be careful driving it during testing as it won't stop as quick. If it does go away then you know it is the ABS, now this won't be cheap, especially if you go factory setup. If cost is a problem you could try a used one from a wrecking yard, most will carry a part only warranty. HTH
dear tennisshoes, i will have the GM dealer disconnect the ABS module tomorrow and start driving it. thank you for such a quick answer. anything i can do for you? best, roger
Good luck with having a dealer do it, something about liability. This something you will have to do yourself as a diagnostic tool.
It might just be a wheel speed sensor or the wiring plug in. The fun part will be finding which on of the 4 is at fault.
If that was the case Bob it would have a light on for sensor error or connection.
Not necessarily if it were intermittent. My 2006 did a couple of odd deals like that and when the fun was over the traction control light went off and no further issues. I don't think that the ABS module would fire up by itself, but certainly I could be wrong. Also mine was a C6 and his is a C5. I highly doubt the his dealer will even discuss disconnecting the ABS unit. If it were mine I would inspect all the wheel speed sensor connections looking for chaffed wiring and corrosion at the connector.
A good read on the active handling system is at the link. It may not help fix the problem, but understanding how the system works could be benificial...http://www.corvetteactioncenter.com/tech/c5/activehandli ng.html
I just got off the phone with a troubleshooter buddy and he has ran across some of those that did not turn on a light or leave a code, and the wheel sensor was out of specs, he also told me that he has seen about three Vettes that the ABS has kicked on for no apparent reason, but it did all 4 brakes, he has never heard of just one wheel, he didn't give me any ideas either. So I stand corrected. Thanks Bob for making dig deeper.
I had just done some research and lots of reading when my car did some strange stuff and learned that even a dirty wheel sensor connection could do this. I believe when my incident happened I was crossing a set of railroad tracks that crossed the highway at about a 30 degree angle and the tracks were wet with dew. One front tire lost a little traction and the other one didn't. It was real fun for about 5 seconds while the active handling was trying to figure out what the heck to do.
I want to thank Bob and tennisshoes very much for their help. This information will go to the GM dealer. Thanks, Roger
One more thing, if the issue is not one of the wheel sensors....the problem could be with the steering sensor that detects and measures steering angle. If this sensor or the associated wiring has a problem it could be telling the active stability control that the steering is moving when in fact it is not. That would tell the active stability control to apply one of the brakes helping the vehicle turn in the direction that it thinks the steering wheel is turned. Early C6 cars had an issue with the wiring coming loose or chafed inside the steering column when using the telescopic function causing these issues. I think the system is somewhat similar in the C5 cars. Best of luck with it and please keep us posted on what the issue ends up being.
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