I have dearched long and hard to no avail. A little help please.

My 1998 LS is no longer my daily driver so there is some significant time between these repairs but about 6 months ago I had a need to change my front right wheel bearing. I bought parts to do both but after I completed the right side I road tested it and had a problem with the ABS kicking in at the very end of my stop - 2 MPH for example. It gave me a VERY slight pull to the left as well but the sound and pedal feeling was definitely the ABS. When I replaced the bearing I also replaced the gear like ring used in the ABS - all Lexus parts.

My diagnostic work included cleaning the sensor and the seating on the hub which didn't work. I then pulled the sensor and, using a flashlight and q-tips, cleaned the ring. There was really nothing to clean but I went tooth by tooth. All signs point to a bad sensor but there was no rust/corrosion when I removed it so it was hard to believe that the sensor had coincidentally failed.

Here's where it gets mysterious for me. After a while I thought that maybe I should check the left wheel to see if there was a spacer or something missing from the right wheel. I removed it, nice and clean like the right side and replaced it and took a road test. Now the ABS kick in is more pronounced and creates no pull to either side.

I just can't believe that both sensors failed when I removed them...it's just a 10mm bolt afterall. I looked for air gap specs but it seems that there isn't any trick to installing the wheel speed sensor - just plug it in.

Any thoughts before I drop $350 on new sensors? Thank you!

 

try resetting the ABS by pulling the main fuse in the engine bay fuse box and see if anything improves. i too find it hard to believe both sensors went bad.

 

My ABS does it too sometimes. I didnt find a solution to this problem. I read somewhere that air in the brakes may cause it, so try bleeding the brake. I did it, but it didnt help. well, may be a little bit.

 

Well, it's hard to admit this but maybe it will help someone else. I pulled the fuse - nothing. Pulled the negative battery cable - nothing. So I decided to retrace my steps and clean the seating again. Just on a whim I thought I would add the slightest touch of lithium grease to the Speed Sensor gasket. That seemed to do the trick. When I reinserted the sensors they kinda clicked into place firmly. I suppose that the dry (not cracked) gasket just needed a touch of lube to get fully seated. In any case, problem solved - $0. The best solution.

 

I had this very same problem after having a bearing replaced on my 2000 LS 400. I had removed the hub and taken it to a local mechanic to press out the old bearing and press in the new one. After re-assembly at approx. 5mph as I slowed in the braking process, the ABS motor would engage. I was pretty sure it had nothing to do with bleeding the lines because the system had never been opened.

After a couple of hours of consternation and trouble-shooting I figured out what the problem was. It seems that the ABS sensor is so simple to install that you can't do it improperly. Not true ... at least in my case. I took it apart twice trouble shooting and put it back together - no workie. On the 3rd time I got under the car so I could see the "seat" of the sensor. Well ... because of the o-ring on the sensor you have to work it / twist it in to place to get it to seat properly. If you just blindly put the sensor in the sleeve and push it in then tighten down the mounting bolt, it probably won't seat properly. This was enough to have the ABS mal-function !! Glad to have that one figured out!

 

I’m having similar problems with my 99 Ls400 after having removed the front driver side wheel speed sensor as I had to replace my struts and control arm. I will try to see if this resolved the problem.

 

This resolved my problem with VSC engaging!