• 2006 Pontiac Torrent

Occasionally, when coming to a stop my car seems to be engaging the ABS. I say seems to be because I can't think of any other system that would engage the breaks but then again I don't have detailed knowledge of all the systems.

One thing that might be relevant. The issue goes away if I have been driving the car for an extended period of time. In other words, I usually only drive my car from home to work which takes about 3 minuets, and this is when the problem is most likely to occur. However, if I take a trip that requires me to drive for more than 15 minuets or so then the problem goes away and does not occur again until the car has come a to a rest for awhile (at least 4-5 hours).

Some details of the problem: A noise similar to the sound an air compressor makes when you first plug it in can be heard as I press the brake peddle. The noise is accompanied by what would seem to be the ABS engaging; the brake peddle becomes slightly harder to press and the braking system seems to engage and disengage rapidly. I am assuming this is how the ABS system operates when it is engaged.

This is not a new problem. I am just recently able to address it. The ABS light used to be on and accompanying the braking issue until recently when I took it to a mechanic. He said there was a bad sensor in the front of the car on the driver's side so he replaced it. I figured this would fix the problem. Although the ABS light is no longer on, the braking issue I have explained remains.

My question is, what do I need to tell my mechanic so that he can make a proper evaluation of the right system in order to fix this issue? I would hate to take the car back into the mechanic and just say: "yeah the light's off now so thanks but the ABS is still engaging; the sensor hasn't fixed the major issue here" without having a clue as to what the major issue is myself.

  • Welcome to Motor Vehicle Maintenance & Repair! It seems you've covered the bases within this question. If the ABS light isn't coming on, it's going to be hard to diagnose. Also that the problem goes away after several minutes of driving is another thing which will make it hard to diagnose as well. Really I think your description of it is really going to tell you what's wrong. Is it actually the ABS which is engaging or is there a slight warp in the rotors (or the rotors weren't bed correctly) which is going away when the rotors get completely warmed up. It could possibly feel the same. Aug 20, 2018 at 17:58
  • @Paulster2 Is there something I can do on my own to narrow it down? Would I be able to diagnose a warped rotor or improperly bed rotor on my own?
    – Rob
    Aug 20, 2018 at 18:58
  • I think it would be very hard to diagnose without knowing exactly. I hate to give you that kind of answer. Really, I suspect you need to take it back to the mechanic which did the work and tell them it still isn't behaving as you'd suspect. Give them the information you've given above and go from there. Someone on here might be able to give you an answer, but first hand is going to be much more accurate than through here. I've not heard of it, but the ABS system may just need reset or something simple like that. Aug 20, 2018 at 20:09
  • A bad sensor/improper spacing can cause abs activation without setting the light on but will usually generate a code. Honestly a scope would be the way to go. Since it’s probably a passive system i would guess the amplitude on one or more sensors is lower than others when coming to a stop. Depending on the setup you can check the sensor hole for rust build up.
    – Ben
    Aug 20, 2018 at 23:09
  • @Ben - Why would the issue go away after a little while, though? That's what's got me stumped. Things like this usually happens because of things heating up, and this may be no different. Aug 21, 2018 at 0:30


You must log in to answer this question.

Browse other questions tagged .