ABS activating with no brake.

Twice in the last three days my ABS has activated without warning (startling the hell out of me). The common denominator between both instances has been the road condition/design, here's the facts....

Condition: Descending right hand curve with a dip at the apex (two seperate but very similar locations), seems that as soon as the passenger front suspension loaded the ABS began grinding with lots of pedal feel and the VSC beeped accordingly.

History: Truck in for an alignment and tire rotation about 3 weeks (1500 kms) ago. Never happened before and clean bill of health leaving the dealer where a long time friend works and exclusively is requested to work on my truck.

Truck details; 2010 TRD DC LB, 50k kms, Billy 5100's in front set at 2.5", LR UCA's, 2.5 " AAL in the rear with Billy's, 265/70/17 BFG At's, stock wheels.

My first thought is an ABS sensor has been compromised in the passenger front wheel during it's last shop visit but a visual inspection by myself with limited skills reveals nothing. Is it possible that the suspension compressing is playing havoc with a sensors wire routing? I would appreciate any thoughts the good folks of TW may have .....Cheers and thanks, squad.

 

When the VSC / traction control engages , you get a beep beep beep and the brake pedal pulses the same as when ABS engages

Your VSC / traction control engaged

 

Absolutely heard the VSC beeping OZ but the pedal grind feel and noise of the ABS has me perplexed. Typically when my VSC engages (snow etc.) I hear the beep but dont't hear/feel the ABS.....Or so I recall.

 

its the VSC

 

It's when the traction control portion kicks in , that's the ABS like pedal grind and pulse you hear.

I have the same thing happen occasionally .

Did you notice the truck push in the corner ? ie , not turn ?

 

The exact same thing happened to me when I spun around on the freeway after losing traction. I heard the grinding sound, I thought it was my tires from sliding sideways. Perhaps not feeling the ABS in the snow was due to it not gripping at all in the slippery icy road. The difference in alerts between your situation and mine is that for the duration the dash light icon with the squiggly lines under the tires came on.

 

The VSC was so bad after my lift i had to pull the fuse and i have never looked back.

 

Thanks bt......I'm certainly willing to admit that my memory may be foggy with what happens when the VSC activates because I call on it very, very rarely. If it is indeed my VSC engaging and not my ABS I wonder why now twice in a couple of days and never before. Surely I have met those road conditions many times before and never gave it a thought because there was no issue.

 

Interesting, I have run this very setup since the truck was brand new off the floor without any trouble...

 

My truck must be stupid than because it never learned, even after a reset.

 

I've come to the conclusion that there is two levels to the VSC system , one where it beeps alerting you to wheel spin and it corrects it without brake involvement and one where it beeps and senses a condition that triggers the ABS style braking to correct what it perceives as a roll over or tail slide condition

 

Perhaps with your new alignment the truck feels the road differently now.

 

Are you talking about how some trucks need the yaw sensor recalibrated after a lift?

 

no expert on toyota's system but most if not all stability control systems use braking at whatever corner(s) deemed necessary to control skidding/ rolling. your turn sounds a bit like one that would make traction loss easy whether braking into it or accellerating through it. drive slower through it and i bet its fine.

im sorry guys but these systems sound like such a pita i thank god every day for my "old" truck. really jealous of that auto lsd though

 

This is something that I didn't know, thanks. My plan is to take it back in and talk to my buddy the Toyota tech but I was hoping to generate some Saturday night discussion and learn something new.

 

There is a pdf in the first post of this thread that outlines the recalibration procedure

http://www.tacomaworld.com/forum/showpost.php?p=691254

 

Thanks OZ, appreciated.

 

No problem Marc

 

I have the same thing and here is the culprit: two nicks/breaks on the ABS wire. Just ordered a new wire assy. from eBay, but I will be taking my truck into Toyota in two days for the rust and leaf spring warranty inspection. They may be replacing it for me before I get the new wire in.

 

when you hear the beeping, you can also hear the abs. I've done this dozens of times in the snow