gandeboz

noticed sometimes when i accelerate hard or just the odd occasion when i apply the brake pedal it vibrates for like 2 seconds like a toy. definitely not the same as ABS feel. my brake pads have been replaced and rotors have alot of life in them. any solution to this?

torquetube

There is a 270° highway offramp where I can reliably get my car to do the same thing, every time. If I come in hot, and lightly cover the brakes in case traffic is stopped ahead, the pedal suddenly firms up. I can feel vibration through the pedal that's nothing like ABS, and Active Handling is not applying brakes differentially. No message appears on the DIC.

I assume it's some sort of pre-Active Handling mode, where if you've got lots of lateral acceleration and it looks like you're about to throw it away, the EBCM kicks in, ready to override any pedal input that upsets the car.

sailmaster

Have you checked your rotors lately

buckmeister2

How many people do you think really know how to "check" rotors? He said there was "a lot of life left in them".
Maybe you meant to say, "Take your car to an independent shop and have them check the brake rotors for hot spots or uneven surfaces".

OP, I am not sure what you mean when you say it sometimes happens "when i accelerate hard". Did you mean when you "decelerate" hard?

gandeboz

no i accelerated hard and when i was about to put my foot on the brake pedal it felt like a vibrating toy for a second, i feel like its faulty brake pedal sensor

Dano523

With pressure on the brakes to slow the car down, or intial contact with the pedal before you into the brakes hard isntead.

If into the brakes, and the pedal starts to vibrate up and down, that is the ABS kicking in. Hence pedal will pulse up and down a short distants very quickly when the ABS kicks in.

If just as you are applying pressure to the pedal and not deep into the brakes yet, that would be either brake booster, or rotor surfaces are not true instead.
Note, if you are buying after market rotors, take them down to at least have them spun up to make sure that the rotors have been ground correctly to the wheel hub mating surface. On some after market rotors brand new, have seen the rotor surfaces out of tram to the hub making surfaces so bad (over .030"), the only want to correct them is to turn them. On used rotors, can end up with high and low spots on the surfaces, and the only way to fix such is to turn them as well.

Also add, have see cases where the face of the wheel hub was not cleaned, or mating surface of rotor with debris between the two, and this can cause the rotor to be out of tram with the hub as well.
So for most of use when we pull the rotor the first time, will remove the rotor washer type keepers and not replace them, but if you are pulling the tires to swap sets often, then not a bad idea to buy some more keepers to hold the rotor tight against the hub when the wheels are swapped so you don't end up with derbriesbetween the two during the swap.

Note, if you are running after market rims, some of the rims are not relieve cut for the rotor keepers, so if such is the case, then don't reinstall the keepers/make sure they are removed before installing the rims.
Hence oem rims have a secondary cut channel so they clear the rotor keepers/retainer in play, so the inside of the tire mates up correctly with the face of the wheel hub face. On some after market rims without out the secondary channels, this will cause the rim to not tram/square up correctly with the face of the rotor isntead.

Two rotor keepers/retainer still on the studs.