ABS kicking in a low speed, coming to a stop

i posted earlier thinking this was a low-speed coming-to-a-halt transmission problem. I swore it was gear noise. Road test at local transmission shop, owner laughingly says "NO, that is the ABS solenoid kicking in on a square wave and pulsing your brake lines! Feel them?" Yep, I did. The grinding sound wasn't the differential or the clutch or the transmission.

Now - background - I replaced both the front axles. They had the reluctance ring gears on them, the new ones. I didn't bother to count the splines. They seem like decent replacements for the old ones. When I put the calipers back on, I didn't correctly install 1 of the 2 front ABS sensors. For a day or so, the ABS light was on. When I found and fixed the ABS sensor, the ABS light went off again.

When I come to a stop from any driving speed over 20, as the car comes to a full stop, the ABS suddenly kicks in... no ABS light... and the ABS gently pulses the brake lines until the car comes to a complete stop, then it lets off the brake line and you can feel it "let go".

What would confuse the ABS to think it needs to engage at speeds 5MPG or slower, and then hold on until the car comes to a complete stop? Did I break it? Is it confused? Does it need calibrated? Are the axles spinning at different speeds at slow speed and ABS thinks "oh oh I am slipping!!" ???

 

oh. Not the only one.
ABS kicks in at slow speed all the time | Toyota Nation Forum

 

My abs would engage randomly at low speed stops. I was very confused as well and contemplated doing the relatively complicated abs delete as I thought the abs ring gear had missing or broken teeth. My symptoms occurred after doing work that required the sensors at the wheels to be removed from their sockets. I turned out to be a pinched o-ring not allowing the sensor to be positioned correctly. I made sure that all sensors were seated properly and the securing bolt was tight. I also cleaned the sensors. Has not occurred once since carefully repositioning the abs wheel sensors.

 

This video details out how to pull codes from the ABS system. It follows the procedure in the FSM:

https://youtu.be/dGQtEDfnATM

There can be codes present without the light on. Code readers also don't pull the ABS codes, so a chain store won't be able to helo you there.

I had a similar issue (low speed stop, abs kicked in, and I had to rebuild a section of my neighbor's fence). Before I performed the FSM diagnostic procedure, I removed and cleaned each sensor, and especially on the rear, I removed each harness (including the connector up by the rear frame rail) connector and cleaned them with contact cleaner. Everything worked flawlessly after that, and no codes were present during the check.

Edit: Also, apparently the pins required to read the codes are not present in the pre 01 interior ODBII port, but there are comments in that video which detail the right pins to jump in the engine bay diagnostic port.

 

milegae at time o repair ?????

retrace Ur repair

be certain the spline count is CORRECT

be certain sensors are in Correct positions

 

Sorry, I reread your OP... When you say "front axles", what exactly did you replace? Do you have Manual or ADD hubs?

For the 4WD (ADD) and PreRunner 6 lug tucks, the ABS tone rings are part of the bearing stack, not part of the "axle".


Axle / CV Assembly:


So if you can provide a little more information about your truck, and what you replaced, we might be able to help more.

 

it was tone-ring grit that got me. I took out the front ABS sensors, cleaned 'em, cleaned up the tone rings, and the ABS grind at slow speeds went away.
Thanks guys!

 

Can you provide a bit more information about your truck, and what & how you cleaned to help future searchers?

Specifically how did you clean the front tone rings?

On my '01 4wd, cleaning the tone ring is extremely difficult, because the only access to it is through the ABS sensor port unless you remove a the inner seal. So I think it would be prudent to give future owners a good description of what you did.

 

I took off the ABS sensors and stuck a Q-tip down in there. Several of them. Some of the grit was just grease, some of it looked more like stone bits & grease. something solid-ish mixed with the grease.

 

Thanks for clarifying! It's important to share the knowledge in the community.

Can you please clarify what you replaced, and what spline count you were referring to so that others get the full picture.

For what it's worth- one of my favorite tools is made from old windshield wiper blade steel backing piece. Next time you replace your blades, disassemble the blade- there are two pieces of spring steel in there- they are great for little pick tools.... or reaching down into the tone rings with with a bit of rag wrapped around them.

That's what I used to clean my front tone rings. But to be fair- The material on the tone rings was grease from the failing front bearings. So keep that in mind as you asses how contaminates might have found their way onto your tone ring.

 

I'm guessing because I was kicking my half-axles around in the mud and dirt before I put it in.