qha_vn

i was in a situation tonight when i needed to brake hard at around 80km/h, i heard the sound of tire sliding on road surface, the car still came straight but I wonder if ABS had worked properly.

from what i understand, ABS wont allow a wheel to slip, but why i still here that sound? and how i can be sure that ABS is working?

LS400 with 90k miles on clock

jcrome04

You will feel the brake pedal pulsing when ABS kicks in. Sometimes there is an ABS light on the dash that lights up too when it's engaged. I've never had it endage in either of my Lexus'.

Lexuses71

Jchrome is correct, that's how you'll know if it's working.

Neofate

iTrader: (1)

All I can add to this is I've had ABS go off one time in my life.. In my Nissan 91 300ZX. Was little wet outside, and was coming to an offramp. The person in front on me slammed on their brakes because they didn't see the line of cars completely stopped in front of them. I slammed on mine, and just slid the car to the 'service lane' on the right, in case the brakes didn't do the job.

I remember distinctly the brakes working perfectly, just very odd. In the 300ZX they were quad piston calipers.. and the brakes in ABS mode stutter in X millisecond intervals. So with brake pedal slammed, the car would chirp in a very quick pattern. As the wheel would lock unlock lock unlock etc.. I suppose once it sensed the front wheels sliding (in a rwd car) it knew to release the brake, when they turned again applied, and so forth. (Not that I know the technicalities of an ABS system.. but it works)

I'm surprised I haven't used it more than once in my life.. maybe they have refined it where it doesn't 'stutter brake' I have no clue.

If they haven't,.. there is no doubt you would know when it was working, unless it , perhaps, only worked for a split second and then the car stopped the skid.

PureDrifter

iTrader: (10)

ive noticed its a lot easier to feel/tell ABS engagement on my 99 than it was on my older 95, prolly since lexus integrated the ABS with the VSC system and made it a touch more sensitive.

CK6Speed

iTrader: (1)

Wait until it is wet then slam on the brakes Seriously though that is how I test mine out. In the old days, the ABS solenoid would stick causing expensive accumalator and/or modulator replacement. To keep the solenoid valves from sticking it was advised you exercise them. To do this you could tap the the ABS relay, or simply active the ABS system by slamming on the brakes in the wet. Todays cars I don't think you need to exercise them anymore as it does it by itself, but I still activate the ABS on my cars every once in a while just to check.

valex

I recenlty noticed that ABS on my 1999 LS got way too sensitive and actually kicking in on dry pavement, never, it never did it before. I changed the rear half axle and a rear speed sensor recently and don't know if it has anything to do with the ABS not working properly. The problem started after I changed the ABS sensor and the dash light went away.
Could it be that I didn't install the Half-axle correctly?