ATRAC / Traction problem

Help! Long story, stick with me.
My 2019 TRD OR has started doing some weird stuff. In 2H at lowish speeds, under 30 it is randomly doing what in my uneducated opinion feels like it is cycling the brakes like the ATRAC would do when a wheel is losing traction. This is on dry pavement in a straight line. Does it for a few seconds then stops and drives normally again. I just happened to be on my way to the dealer to get some TPMS sensors programmed. Luckily it only started doing it on the last half mile of the drive. Made the service rep jump in with me and drove down the street to show him.
Of course later on when the mechanic test drove it he could not replicate the fault.
The service tech said that they could not find anything wrong with it.He suggested there was evidence of rubbing and that the rubbing my be causing the the ATRAC to activate. I just put 285/70s on about 2 weeks ago. Pretty sure the rubbing was from my drive home from the tire shop and that after a small trim and liner push it no longer rubs and sure as shit it doesn't rub driving slowly in a straight line. If it was rubbing enough to slow down a wheel I think I would notice. I think they just filed it in the too hard basket. The ATRAC warning light illuminates while it's occuring. During one of these episodes I also noticed the Multi Terrain Select Not Available light flash for a split second. Obviously the MTS was not selected on.
I am going back to the dealer to pick it up tomorrow.
Any ideas or experiences.

 

You bought this vehicle new? If not, did it ever have anything done to the steering angle sensor?

 

No, purchased it used. Had it for about a month. No idea about the steering angle sensor.

 

Not exactly the same issue, maybe you need zero point calibration done after putting different tire size?

 

I’m thinking it needs the sensor or it needs to be recalibrated.

 

285/70s and a lift? Have you checked to see if the tire is rubbing the UCA

 

Isnt the abs line notorious for getting stretched out and causing these issues?

 

ATRAC is only available in 4Lo so definitely not that... if it is you have greater issues. The traction system is similar but less aggressive so you're likely triggering it somehow. Most common cause is a faulty/loose/caked ABS sensor or potentially a tone ring that got whacked/caked. The only way rubbing would cause it is if it is slowing the tire enough but that also means skidding the tire. That's not something that just happens incidentally.

 

Only 2 inches of lift and seemed like there was plenty of slack but I will definitely check it again when I get it back.

 

Sounds reasonable. Do you know if the sensors can be swapped out easily or does it require some kind of programming or calibration.

 

Sometimes you do, sometimes you don't... If I got codes on the post-repair test-drive I'd run the system calibration but I often didn't need to depending on what failed. Normally zero point failures threw codes for out of bounds readings. Intermittent issues like you described were typically mechanical or electrical failures.

Ideally I'd start with a calibration as part of my diagnostic hour but too many shops will test drive, throw it on the rack for a visual, and ship it can't confirm.

 

Any chance of rodent damage to wiring?

 

Sounds like you got an abs sensor dropping out at lower speeds causing abs to kick in thinking it's a wheel that's locking up.

 

That's it right there. ABS sensor.

 

Thanks for everyone's input. Way more helpful than the dealer. I sware some of these guys wouldn't know the tire was flat unless the diagnostic tool told them. The art of good old fashioned trouble shooting is being lost. Anyway I got the truck back. I gave up when the service rep started talking about a viper cut for my non-existent rubbing. Definitely no rubbing anywhere and plenty of slack in the sensor wire at full articulation and I am confident I didnt damage anything when I installed the new coilovers.
My next plan is to disconnect the battery and replace both front sensors. I should have paid more attention but I think the ABS was activating the right front brake. If that doesn't work my next step will be to get a zero point calibration, hopefully I can get that done somewhere other than my local toyota dealer.
Does that sound like a reasonable strategy?

 

My local dealer quoted me $300 for a zero point calibration. I declined and did it myself in 15 minutes using two paper clips.

 

If you were the one that installed the Bilstein shocks with the oem springs, you'd know if there were any issues with the abs sensors during the install. It's been 4 years since I did my Eibach shocks, and don't remember having to do anything with the abs sensors...

 

I saw a post about that method. That actually works? Sounds pretty dodgey. Maybe I should try that before I drop a few hundred on new sensors.

 

Update.
I took off the front sensors and they look brand new. Looking through the hole while rotating the wheel the tone ring looks new as well. Truck only has 33k miles on it.
Tried the paper clip zero point calibration. Got all the correct flashing lights but now my VSC light is on permanently which only came on before intermittently when the vsc was faulting. Looks like a trip to the dealer is in my future. Side note, my VSC button does not seem to work.
Took it to AutoZone to use their scan tool and it came back with VSC fault but no codes or anything usefull. No shit Sherlock!

 

Update.
I purchased an OBDII cable and the Techstream software on Amazon

VCI J2534 Cable Fit for Toyota TIS Techstream - Latest Version V17.00.020, Firmware V1.4.8, OBD2 to USB Diagnostic Cable, Support Win XP WIN7 WIN10 32/64bit

https://www.amazon.com/dp/B0BV2XB5KG?ref=ppx_yo2ov_dt_b_product_details
and with a little help from YouTube
https://youtu.be/3UxSRss3yoU?si=QZbQhaOIxbfVJJZz
I successfully did a zero point calibration clearing the fault light. Will wait and see if this helps with my initial problem. Techstream is not showing any fault codes for my ABS sensors. Due to the sporadic nature of the issue I suspect it will only throw a code when its actually happening?

 

If your problem continues, I suggest consider "shuddering" - it can occur for a couple of seconds when driving at low speed -30 to 40 mph and low engine RPM 1200 to 1500 .
If driving in 4S instead of "D" on a route that repeats your issue you have good clues for Toyota Flex Lock torque converter failure beginning.
This happened to my 2017 SR5 at 48,000 miles.
Repair was a big deal and I would be glad to help you if this issue fits your problem.

 

Did you check the full length of the abs wires? It’s not the sensors themselves that can be damaged installing suspension, but accidental damage to the wiring as things are pulled off or worked around. I’d suggest carefully checking them for nicks or damage to the wire insulation. Especially around the brackets where they are mounted on the spindle.