ABS/traction control failure help
 

Hey guys-

Hoping someone has had a similar experience or maybe help shed some light on a problem.



When I had the car out for the last track day, I experienced a rather unusual sensation driving to/from the track-

The car felt like it was tram-lining REALLY bad, like it had 305 series tires and a flat alignment (and it doesn't). The back end was walking all over the place. I mean it would drive straight, then I'd feel the back end "dance" around like I was going over uneven pavement, then it would stop. Then do it again. All while I was driving straight, or through gentle curves.

On the track --where I run pedal dance mode-- the car felt rock solid and stable. Driving that same the stretch of highway/road in 'pedal dance' mode to get gas - it maybe felt a bit better, but still the type of same swaying behaviour.

Fast forward to the last track session of the day, and after several laps the left front wheel locked up REAL bad. Completely caught me off guard, flat spotting and ruining the relatively new AR-1.

I cruised back to the pits and noticed the "stability control" (?) idiot light in the center of the dash was now lit up (ie not the one to the right that lights up with pedal dance - it was already lit) and the ABS light was on too.

Let the car sit for a while as I packed up, and when I restarted it, ABS and trac light were off, but it exhibited the same 'swaying' feel as I drove home. Took it for a bit of a cruise after unloading, and maybe 10 miles later those 2 lights lit up again.

At that time I pulled over and felt the rear wheels and they were warm to the touch, even though I hadn't been braking hard, which makes me think this is somehow tied in to the stability control system.

If it is - what I don't get is why I still experienced this in pedal dance mode on the road/highway but NOTHING on track?


Any ideas what I should be looking for? The car is parked a few hours away from me and I'd like to have a plan of attack to check it over when I go back.


My initial thought was a wheel speed sensor, but I don't get how that would affect things in pedal dance mode?

Next thought was the clock spring, but then I remembered that after having issues with it a few years back (when I went to an aftermarket steering wheel) going into pedal dance mode stopped those problems cold.


I tried to pull codes off of it when the ABS light and center-dash traction control idiot light were both on, but got no codes using the OBDlinkLX :(

Just to clarify the 'center dash idiot light' I'm referring to is the light that flashes when the traction control system is doing it's thing/notifying of a loss of traction - except it's staying on solid.

I'd check anyways, pedal dance doesn't disable ABS. (https://www.ft86club.com/forums/show...4&postcount=13)

Anecdotally, a friend recently had similar issues with TC lights and power steering lights in her Civic. Car drove normally, but she's not a big car person so idk if that means there were issues that went unnoticed. Turns out it was an ABS magnetic encoder wheel which is integrated into the bearing assembly. Replaced the bad assembly, TC and PS lights went away. May be worth a look, there were no codes the independent shop could pull and it required a dealer to diagnose in the end. I'm seeing a similar setup in our hub assemblies, so it's a potential route to investigate.

The bearing itself is also suspect. If it's failing and causing friction there could be abnormal heat build up. Also, a stuck or failing caliper could put excess heat into the wheel.

Lots of room for minor issues to mess with the stability control system's ability to make sense of what's going on.

really stupid, but have you checked tire pressures? what about tire wear? in extreme cases, uneven tire wear between the front and rear can have a similar effect as well.

best case to check now, i would pull the abs fuse, and make a few runs checking for the same condition. if everything starts straightening out, your culprit is most likely something at the wheels-- bad speed sensor, incorrect alignment settings, etc.

edit: if your wheel is crooked now, definitely get the alignment checked out-- a crooked wheel will skew the cars readout-- if it think's it's perpetually turning, it expects a different wheel speed than if the car is actually going straight.

Tire pressures were within 1 psi on all 4 wheels hot on track, and the same when cold.

Tire wear was essentially even all around.


Good advice on the ABS fuse - I'll give that a try. Is there just a single fuse I need to pull?



The steering wheel being off caught me a bit off guard too. I was positive it was centered at the last alignment and it's only seen maybe 500 miles since then with 80% of that on track.

The alignment felt spot on on track, but maybe that needs to be checked.

If you drive the car hard, the wheel will not stay centered after alignment. The EPS coupler in this car is made of play-doh and failed hopes and dreams.

For the last couple years mine would be fine after an alignment, but after a hundred miles or so the wheel goes off center 10-15 degrees even though the car tracks just fine.

https://www.ft86club.com/forums/showthread.php?t=133606

Interesting! Thanks!!

Am I correct in thinking that the EPS coupler issue won't cause problems with the clock spring?

It shouldn’t.

I replaced the EPS coupler on my car thinking it was done for (it breaks into pieces) but it wasn't. However, replacing it with the Hyundai part (I'd already dropped the EPA to inspect coupler) gave me no issues whatsoever. In my case, the rattle came from brake pads juggling around in caliper (damn potholes).

You take the EPS down from underneath and I believe the clock spring is untouched.

Just a thought, my Porsche has a habit of trying to climb out of the small depressions made by trucks on the highway. The road seems to be shaped like a slight W. It seem to happen with wide flat performance tires. It kind of pulls you right and left.

UPDATE:

So - had the car on the quickjack.

Rear wheels BOTH had lots of play. Thought bearings but they were too quiet for that - and on further examination it was clear the wheels were pivoting directionally - so I pulled them and checked the arms-

And I found that BOTH rear toe arms were loose at the outside joint! Allowing a significant amount of movement and therefore toe change!


When tightened down, the castle nuts are too far past the drilled holes for the cotter pins to lock them in place. I'm thinking hardened washers might help space things out so both top (flat) and bottom (camfered) castle nuts can be locked in place. Or if that doesn't work using a jamb nut-


Need to pick up parts and head back.

Not sure if this is what tripped the error codes or not?!? Changing toe certainly seems like something that could mess up the stability control system - but why the ABS light?

ABS and traction control use the same wheel speed sensors. it knew it was getting erroneous readings, but didn't know what to do with it.