supak111

1999 rx300 swaying in rear when going 40+ mph and holding gas paddle. Feels like stability control/abs is kicking ON every about 2 secs in on the rear left or right wheel and making the car sway left/right. Imaging someone in the trunk trying to shaking the car with their wight left, right, left, right.... Does it for like 30 seconds, then it stops and the car drives fine, then it starts again randomly for another 30 seconds or so and stops again. Its almost like the stability control is trying to adjust the cars direction by applying break to ONLY one of the rear wheels at 2 second intervals. I did the zero point calibration but no traction control lights come on the dash when doing it so I'm not even sure if it was done right.

No lights on the dash btw. Engine, ABS and traction lights are all OFF.

Anyone have any idea what this could be? I'm not even sure if my car has stability control, its a 1999 RX300

JAB

I don't think that 99s had stability control (VSC).

hypervish

That's correct, VSC was standard on 2001 and up but not available on 99' and 00'.

Baetke

Bounce each corner of the car to check the condition of your struts/shocks.
Jack up each rear wheel and wiggle wheel to check for loose wheel or suspension components.
Visually inspect condition of sway bar/bushings.
If nothing shows up, take it to a good suspension shop to have it looked at. Hate to have you lose control of the vehicle if something is about to fail on you.

supak111

I checked to see if the wheels are loose (bearings and control arms) both seem ok. Tire pressure is fine, and the shocks seem fine. I tried jumping up and down on the truck and the shocks absorbs the rebound. I even check if the rear wheels are straight proportional to the side of the car and they both seem ok. I thought maybe previously the car was hit in the rear but that doesn't seem to be the case since all the body lines like up and the suspension arms seems to be all stock on both sides no replaced parts.

Didn't 99/00 have VSC as an option? Is there any way to check if I have it? And is there a way to turn it OFF just so I can see if that could be the problem? If I could disable ABS then even if the car has VSC it wouldn't be able to turn it ON as VSC uses ABS to operate.

hypervish

No, VSC was not available until 2001 when it was introduced as a standard feature. Only TRAC was available in 99' and 00''.

You can turn off ABS if you wish to, by removing the fuse.

supak111

Ok thank you at least now I know its not the VSC doing it. I will try driving it without abs and see if it still does it. Ill keep everyone posted

supak111

So today I tried it with ABS off still same problem. Checked all the control arms, bushings.... again and everything looks good. Nothing is lose, bent... I don't know what else it could be

Baetke

Another possibility could be a sidewall failure. Try rotating tires front to rear.

2KHarrier

That would be my next suggestion. Make sure you don't have a tire that's low as well...

How often does the parking brake need adjustment? Could that be binding somehow?

supak111

Wow I actually just noticed that rear pass tires sidewall looks messed up almost like someone drove on a very very low tire and damaged the wall. I would have never thought that could have been the problem. I will try using a spare or rotating the tires like you guys said and see if it goes away. All tires were different pressures too actually but none were low at least. I will let everyone know if rotation or putting a spare tire on helps.

As for the e-break, does the e-break only apply break to 1 or both rear wheels? I see how that could be a problem if the e-break only applies to 1 rear wheel so if its always touching a little it would make car pull to one side at high speed.

Thanks for everyone's help so far

Baetke

Since you can visually confirm a sidewall failure I would not recommend rotating that tire to the front. The tire has failed and it will be extremely dangerous to drive with this tire on the car. Put the spare tire on and go straight to the tire shop to get new tires. Let us know how that goes. My experience has been that the tire shop will only sell me 4 matched tires, not just one.

JAB

If the remaining tires are good, with useable tread, I would look for an identical used matching tire. I have done that on several occasions recently, with good result.

salimshah

Very good advice here! If you have a visual confirmation, there is no need to further test and potentially raise the risk.

Tire shops have the obligation to only make repairs that would make the vehicle safe. The liability and suit happy society, puts the burden on the expert and that is why they will insist the other tires be replaced, if the treads are worn down in pairs. Yeah, some time they oversell too.


Salim

supak111

Yes I measured how tall both rear tires are and the one with damage to the wall sits like 3/4" lower so that would def make the car do what its doing. I will just have both rear tires replaced. Thanks for every ones help. This one was def a weird one to diagnose so I'm sure this thread will help someone else in the future.