Hey all! I'm new to ClubLexus and really hope y'all can help with my issue.
I purchased 2015 IS250 Sport Crafted Line a couple months ago and it has an issue pulling left and right over different terrain. It still has factory warrant but Lexus cannot locate a problem. They ran a diagnostic, aligned the wheels and it is still unsafe to drive. I took a road trip to Houston driving 70-75mph and I had to have both hands on the wheel at all times because it was veering left/right. Car Fax was clean.
Feedback/comments/suggestions to get this mystery solved.
Thank you!
Randy

 

Welcome to the forum and congrats on your 'new to you' IS!

It's unfortunate your first post has to with an issue, but hopefully a solution can be found.

I think the first thing to establish is that it's not technically possible for the vehicle to pull in two different directions.
If there was a suspension or alignment issue that was causing the vehicle to pull in one direction let's say left, then it will always pull left, and it would be impossible for it to pull right.
Once the alignment or suspension issue was corrected, then it should drive straight afterwards.

This doesn't mean that you're not experiencing what you're experiencing, more so that it's very likely not an alignment issue.

First, and most obvious, place to start looking is the tires. Often belt shifts on tires can cause to wonder across the road. Since you can't rotate F Sport wheels, then inspecting the tires is the first step.

Maybe you can look at the tires and post some info:
1. Make and model of the tire
2. Front and rear sizes (we assume the vehicle has the correct size tires on it, but never hurts to double check, and takes a few minutes)
3. Tread depth and condition (does it have lots of tread left and are the tires worn even...front what you can see)
4. Manufacturing date (this would be the last 4 digits of the DOT number) - First 2 digits are the week, and second 2 digits are the year (if they are the original tires, they were likely manufactured in 2014, or maybe 2015)

 

Thank you for the quick response and suggestions Sasnuke!

I agree that it is unfortunate that my first post is an issue and assumed Lexus would find a problem easily thinking they have dealt with this issue before but apparently not.

All tires have even wear and no obvious sign of abnormality.
The front two tires have a good amount of even tread on them. Continental 225 40 ZR18 Sport Plus Technology DOT 4116.
The rear tires looked brand new as they had the small spikes/hairs on them. Yokohama 255 35 R18 Advan Sport A/S DOT 1918.

 

Seems like the tires are fairly new and decent quality by the brands you listed.

Next would be to double check tire pressure...should be 36PSI all around.
After that would be to check the front and rear struts/shocks to see if any are weak:
-By bouncing one corner of the vehicle at a time, you want to get a good rhythm of the up and down movement then let go of the vehicle on the downward stroke
-At that time that corner should oscillate upwards and then come down to settle/stop
-If it oscillates more than once, then this could be a sign the strut/shock is getting weak...or even possibly leaking

The problem with struts/shocks that get weak is they don't necessary show signs of leaking, but are still soft when the vehicle is bounced.
When they get weak, and you travel at higher speeds, sometimes the vehicle may wander left and right as the struts/shocks are failing at smoothing out the imperfections in the road.

Beyond that, only if one of the front tires has a belt shift that isn't easily visible, then the only thing that's possible is somehow swapping out those wheels.
Perhaps if they have another F Sport on the lot, they can swap the front wheels from vehicle to vehicle and let you try it for a few days.

Really it's a process of elimination now.

 

If it's pulling left or right, could just be your front end is toed out. On many cars, maybe including this one, you can be toed out and still within spec. or even neutral. You want toed in for the best stability. Some degree of tramlining is normal on a sporty car with low profile wide tires. You don't want your car completely numb to road undulations unless you are driving a camry.

i've spent over a decade diagnosing alignment issues on BMW forums, on my own cars, and even aligning my own car personally using hunter racks. so i know a few things about alignment. let me know.

Post up your alignment sheet.

 

Sasnuke - Lexus said they were going to swamp wheels and tires but not sure if they actually did. Since they did not see or experience anything when they drove it swapping wheels may have not helped. The pulling left AND right occurs randomly. I wonder if I suggested the mechanic take my car and drive it a couple days commuting to and from work to notice the issue to then be able to pinpoint the problem.

The tire pressure readings are good. I will try the bouncing one corner of the vehicle and get back to you.

E46CT - thanks for the info. I just emailed my service advisor to see if she could send me the alignment sheet. Hopefully they keep it on record since they just aligned it a couple weeks ago

 

Would you describe the pull as sharp, like when a wheel gets into the rut a truck leaves on the road? Or is it more subtle where it takes a mile at a constant speed and the vehicle is slowly drifts in one direction?
Just out of curiosity, what vehicle were you driving before the IS?
Myself...I drove a US model 2005 Scion xB before my IS...what a difference LOL!!

 

I'm trying to notice a pattern for when the car goes left and right but it is inconsistent. Sometimes when I switch lanes(say left lane to right lane) it will take a more aggressive lane change like its on autopilot. Not all the time though. Then I have to correct it so it doesn't continue right into the ditch. It's so annoying. I don't feel safe turning the AC on or anything besides starring at the road since the car has a mind of its own. I want to love this sexy, beautiful car but it's being so difficult. ha sad but true.

My last vehicle was 2014 VW GLI manual. Before that I had a sweet red 2005 Infiniti manual.

 

Can you ask the dealer to perform a calibration of the steering system?
It would be the Torque Sensor Zero Point calibration and the Rotation Angle sensor calibration. There is a manual way to do it, but it's fairly complicated...the dealer can do it quite easily and quickly with the Techstream...and more accurately.

Technically whenever an alignment is done the steering should be calibrated as it's likely the front toe would have been adjusted, and that can effect the learned value of the straight ahead position of the steering.
It could play a factor in the steering feel if the alignment was out notably.
The reality is that it's rarely calibrated and the adjustments during an alignment are usually minor, barring an accident, so it usually doesn't effect anything.
But you never know how much it was adjusted, so the calibration could be warranted in this case.

From your last comment it kinda sounded like you were wrestling with the steering a bit, and with the electric steering it shouldn't be that way.

 

Did 2015 models have lane keep assist (LKA)?

 

I can assure you at least, that the car is not designed to be this way. I had a 2015 Camry before this, and the IS to me feels much more solid out on the highway than that car did, in spite of the quicker steering. It just goes straight. So, your choice of car, strictly speaking, was not a wrong one.

I'm betting it's something to do with the electric power steering as well. Seems unnatural for it to pull to one side if the alignment is ok. But we'd need to rule out alignment first.

 

I believe it was available in as an option in a package.
Being the OP's vehicle is a Craft Line 250, I doubt it was optioned enough to have.
But then again what do I know...we don't even get the Craft Line in Canada lol!!!

 

The IS is very stable, but if you aren't used to the sensitive nature of the steering, the natural tramlining can make it feel like it wanders.

 

Yeah I don't even know what Craft Line is lol. I just know that if you have the audible and steering warnings turned off for the lane keep assist, the "pull" over the line if you don't have your blinker on (or the 3 blink cancels mid lane change) can feel very odd and artificial. I hated the feeling of it so I turned LKA off completely.

 

I wonder if running different brand and model tires on the front vs. the rear is a contributing factor. I don't do that and I buy tires as a set, then replace all four at once. For a short time in 2017, I ran a different brand/model tire on the right front (it was a tire in decent shape from a previous set I had on the car and I kept it around in case of emergency) for about 2 weeks while waiting for the new set of tires I ordered. The car did behave differently with the mismatched tire. I acknowledge that the wear was also not the same as the tire on the left front.