Traction control kicking in when turning right
 

Hi all,

New to the forums here, and a new owner of a used 2015 BRZ. Pretty much since the first day of collecting the car, I've been experiencing the traction control kicking in (light coming on + sound + vibration) when turning right, even at low speeds (50km/h).

I would say the traction control issue is a symptom, not a cause. Something is causing my rear wheel(s) to lose grip and thus triggering the nannies. Also, sometimes after making a right turn, I can feel the car pulling to the left.

All of this is only happening when I make right turns. Left turns are perfectly fine.

My car is on used stock 86 absorbers and Continental MC6 tyres.

It's been two months. I've sent my car to multiple workshops (Subaru authorized workshop, an external suspension specialist, a tyre expert shop), and nobody can solve the mystery. I have tested with two different stock 86 absorbers. I have rotated my tyres. I have checked the alignment. The wheel sensors are working fine.

I'm at my wits' end. Please help!

so to clarify, all 4 tires are the same age, same wear, and same type? i believe you're indicating this, but want to make sure--there's been a number of cases where people attempt to put higher-wear tires on the front, new tires on the rear, and the difference in tread depth is enough to trigger the system.

when was the last time the car was aligned? do you have a printout of the alignment specs? if the tires are the same all around, the only few other options are going to be the steering angle sensor in the steering wheel, alignment, wheel bearings, or worn bushings in the rear a-arm setup.

Yes please verify wear level/size of all tires first.

Thanks for the responses.

Yes, the tyres (225/45r17) have the same age and wear - about 2.5 years old now I think. Rotated the tyres in Feb, didn't make a difference.

The last alignment was done a month ago. I do not have the printout unfortunately. Got the wheel bearings checked last week and they looked fine.

I can get the workshop to look into the steering angle sensor and bushings.

i really think the problem is going to be in the rear sub frame bushings. there's a number of them back there between them solid car chassis and the wheel assembly, and if some are loose, alignment specs can read correct, but when the car is subjected to loads(acceleration/deceleration/turning), the bushings can be loose enough to alter the alignment significantly and cause the issues you're experiencing.

for wheel bearings to alter alignment, they usually fail significantly enough to make some horrible noises. same with the steering angle sensor-- it's possible, but unlikely. there'd be more symptoms of that as well than just right-hand turns.

i really think the problem is going to be in the rear sub frame bushings. there's a number of them back there between them solid car chassis and the wheel assembly, and if some are loose, alignment specs can read correct, but when the car is subjected to loads(acceleration/deceleration/turning), the bushings can be loose enough to alter the alignment significantly and cause the issues you're experiencing.

for wheel bearings to alter alignment, they usually fail significantly enough to make some horrible noises. same with the steering angle sensor-- it's possible, but unlikely. there'd be more symptoms of that as well than just right-hand turns.

^^^ +2 ;) Not wheel bearings.


Worn bushings, or damaged suspension components. In any case, system initialization after any change is key.

Why would a wheel bearing not do this?

The air gap between the tone wheel and sensor is critical, a loose wheel bearing will alter that air gap, and it's a Subaru, the rear wheel bearings are shit anyway.

At least jack the car up and check for play in bearings, steering and suspension components before theorizing about it for days. That's literally step 2, step 1 has already been brought up: check tire sizes and pressures.

i'm just a hackjob with an internet connection.

It would not do it because, as soundman correctly pointed out, for there to develop that much play, the bearing would be making so much noise that one would have to be a complete dipshit, or stone-cold deaf to not know something was seriously wrong.


The functional range for the sensor is way larger.

So you say, but I've seen some very small radial play influence track control and abs, and though much more rare, I have seen some major bearing play that was still quiet.

I get what you're saying and understand that it's an easy check, but I wouldn't take that bet.


This'll be interesting. Looking up recipes for crow now. ;)


edit: Doh! forgot that OP already checked them. Oh well... I guess big picture, yeah. Also, hard experience trumps all. On which platform have you seen it happen?

Let’s assume that the Torsen differential is not contributing to the problem. What happens when you turn off the traction and stability control? I would first look at the wheel speed sensors and/or associated wiring for defects. Have you or anyone else checked for diagnostic codes? I’m not certain about the Subaru, but some faults will only register a preliminary fault code and then when a certain number of faults are registered in a period of time then it will trigger a MIL code and the light will come on. I have seen chronic problems that escaped the check engine light coming on. Making right hand turns will cause the left and right and front and rear wheels turn at different speeds. If a wheel is erroneously read for speed, the system will correct for it. One time a friend’s pickup had a code show up for a bad camshaft position sensor and a bad wheel speed sensor almost simultaneously. Talk about a “WTF” moment. The left rear wheel would lock up while making turns. We thought at first it was a repeat of when a mechanic mistakenly added a viscosity enhancer to the differential. That version of limited slip differential did not require additives. A week later, a buddy’s’ 98 Lexus simultaneously developed a manifold leak and a bad O2 sensor. Completely unrelated problems can steer your focus away from fixing each separately.

Pretty much anything, I'll get cars and trucks that get undesired ABS or track control activation either when coming to a stop, setting off or turning a corner, check 'em out and there's a bit of play in a bearing, a bit of rust on a tone wheel, a bit of rust under a wheel speed sensor pushing it out 1mm.

I remember a damn lexus RX330 that had the right front wheel speed sensor coding for tone wheel performance because it was getting pushed up by rust. Of course the sensor broke in the knuckle, drill it out, roloc the mounting surface, grease it up reaaaaal good and slap a new sensor on it... Now that wheel was fine and not throwing a code, but the entire truck was now getting unwanted abs activation/no codes on the other 3 wheels because they also had a bit of rust under them. FML y'a know right.

These little shits are sensitive. The ol' classic are the older Ford Escapes, rust grows in between the front CV shafts and tone wheel and it cracks, so one tooth has like a .5mm spacing difference, and yes, that's enough to make the abs kick in.

Of course, I say subaru rear bearings suck because it's not abnormal to get an impreza/xv/outback/forester in with 2 destroyed rear wheel bearings, it's not even a surprise anymore.