Abs Activates When Braking.

[RobertLx]

Got a 99 RX. when coming to a stop, the ABS activates on dry pavement.

It seems worse on off ramps from the highway. When the off ramp turns and you brake, the ABS activates.

There is no VCS on the car. No ABS light comes on. No check engine light.

Any ideas?

[gordonw]

If the abs is activating on its own, then its either bad speed sensor or worse, need an axle shaft.

[mikey00]

Got a 99 RX. when coming to a stop, the ABS activates on dry pavement.

It seems worse on off ramps from the highway. When the off ramp turns and you brake, the ABS activates.

There is no VCS on the car. No ABS light comes on. No check engine light.

Any ideas?

If you are interested in troubleshooting it yourself, find and download the 99 RX repair manual on this site. It has a pretty good section on troubleshooting ABS problems.

[marie1104]

This is the exact same problem that I am having with my 2000 rx300. The abs kicks in EVERY TIME i brake. I have no idea what can be causing it. I too do not see any lights coming on. How much do drive axles cost?

[puggy]

My 1999 RX300 does the same. I have replaced a drivers side rear abs sensor when it broke as I tried to remove and clean. I've done all the troubleshooting in the manual. No luck. At least one or more of the sensors is picking up a speed mismatch. I have seen a few posters with the same problem. I suspect a Lexus dealer knows what the issue is, I guess this is the next step.

[lenore]

could it be debris on the speed sensors? I took the two front ones off and they had filings on them, cleaned them, but I have not experienced any problems.

[wwest]

could it be debris on the speed sensors? I took the two front ones off and they had filings on them, cleaned them, but I have not experienced any problems.

Tire circumference different L/R ? Tire inflation, wear rate?

[carguy07]

My 1999 RX300 does the same. I have replaced a drivers side rear abs sensor when it broke as I tried to remove and clean. I've done all the troubleshooting in the manual. No luck. At least one or more of the sensors is picking up a speed mismatch. I have seen a few posters with the same problem. I suspect a Lexus dealer knows what the issue is, I guess this is the next step.

I would clean the sensors before doing anything else: http://www.clublexus.com/forums/showthread.php?t=285023

[mikeytt]

My 1999 RX300 does the same. I have replaced a drivers side rear abs sensor when it broke as I tried to remove and clean. I've done all the troubleshooting in the manual. No luck. At least one or more of the sensors is picking up a speed mismatch. I have seen a few posters with the same problem. I suspect a Lexus dealer knows what the issue is, I guess this is the next step.

I would clean the sensors before doing anything else: http://www.clublexus.com/forums/showthread.php?t=285023

the problem is in the abs ring on your'e front drive shaft, you'll have to find out which side it is and change the axle

[SKperformance]

Common issue is the wheel bearing is worn and when you hit the brakes it goes out of spec easily.

Get all 4 wheels checked for play .

[wwest]

If you have EBD, Electronic Brakeforce Distribution, as my '01 AWD RX300 does, EBD activation will feel a lot like ABS. Poor, or even unbalanced HARD braking on just one wheel will often cause EBD to activate. Apparently even slightly disparate braking force will sometimes trigger EBD. I most often feel it activating on a slightly wet downhill roadbed that is just a tad bumpy.

[bobitchin]

my '99 does the same thing. I had a mechanic check it out this week and there is a reluctor ring as part of the LR axle that's cracked. The ABS senses that there is a difference in wheel speed due to the cracked ring. I'm looking for a rebuilt (no luck so far) or even a used axle, new ones are abt. $800

[charles88]

It could be a abs pick up ring!

The abs pick up ring just looks like a cog. The abs sensor works like a magnet and it detects the gaps in the abs ring when the wheel is turing, like the gaps on a cog in between the teeth.

If the abs cannot detect this it triggers the abs, this can be cause by a corroded abs pick up ring or a cracked one!

The fault can be intermittent and won't put your abs light on!

A simple visual check of them will tell you if they are ok or not!