I have 2014 Audi A4 and recently I drove on 1 inch snow and on sleet. I noticed when I tried to brake gently, I felt like something is pushing me back for a sec or two. I didn't feel anything while driving on dry surface of road and braking. What could be the reason? Is it normal?By the way, I hear a slight brake squeak sound when I press the padel gently and I am not sure if it's related with it.
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1 Answer
What you're describing sounds like the pulsing feedback that the ABS (antilock braking system) provides when it actuates on a slippery surfaces.
The best way that I can describe it is as a roughness or rumble in the brake pedal, usually it is accompanied by a matching (for lack of a better word) sound. There may also be a annunciator light in the instrument cluster that comes on when the ABS activates.
It is perfectly normal and serves as a warning that the car is on a slippery surface and that one or more of the wheels was getting less traction during braking. As you're probably suspecting by now, you don't feel it on a dry or even wet road because the system doesn't usually come on.
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Thanks. I thought something broke and causing that feeling. By the way just curious, what does ABS do at such a low speed (5-10mph) while driving on sleet/snow. I read that it helps in steering while braking at high speed.– TanCommented Jan 8, 2017 at 5:22
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What it does is something like pumping the brakes, so that it modulates that force applied to each caliper to match the wheel speeds – this maximizes braking power while at the same time preventing unequal traction from causing the car to start to slide. At speed the behavior is similar, it can apply braking to "steer" the car and help keep the car going where you're pointing it. I think some of the fancy systems will kick in even if you're not braking – for example if you hit a puddle or a patch of slush on the road.– dluCommented Jan 8, 2017 at 5:59