2019 Kia stinger GTS losing power on the freeway after reaching a certain speed

[7Andrei7]

For what it's worth, it's UNLIKELY that it's 2 wheel sensors...

If you have access to an oscilloscope and a multimeter, you can test the sensor, see the last page here.

I also think it's unlikely for both sensors to randomly start reading a 1-2% higher speed. They don't have weird oscillations or something like that. Or if they have, they don't show up.

For me, the things that changed on the car, just before the problem started, are:
- rear tires
- rear diff (from open to limited slip, both OEM and correct spec based on VIN)
- rear suspension was taken apart and put back together
I did a complete reset of the computers.

Next I'll put my summer wheels on and see if that changes the readings. Sadly I don't have time to do it just yet.
I was even thinking to put just one of the summers on the rear and drive at 80 km/h to see if there is still a 2 km/h offset to the front wheels.

 

[7Andrei7]

I have incredibly fixed it!!!
It was...... the tires. I'm not yet sure how I'll approach it with Continental but here is what I did.

As I showed before, with my winter setup, OEM spec 225/40R19 front and 255/35R19 rear with Continental TS860S on the OEM wheels I have a difference in speed read by the ABS sensors of approx 2 km/h while cruising at 80 km/h. If I floor it at higher speed, the difference between both rear wheels and both front wheels can spike up to 5-6 km/h. In those scenarios, the TC steps in and cuts power. This is the first video below.

Last night I decided to put my summer wheels on the left side, both front and read. My summers are the same OEM spec Michelin PS4 on OEM wheels. Immediately I could see that the summers (left front and back) recorded the same speed while the winters recorded a 2 km/h difference (rear front and back).



Then, I put on the full summer set and went on the highway and did a few flat out accelerations from 80 to 150-160 km/h. The speed of every wheel stayed consistently within 1 km/h of each other. Needless to say, there was no TC intervention. Video below.

I'm pretty sure I've gotten to the bottom of it but here is still one pressing question: WTF Continental?!?
I will contact them and try to send out one front and one rear so they can professionally measure it and tell me what in the world is going on.
Opinions?

 

[Snowwhite]

I bought 265/45/20 tires for my wife's car. then she got a nail in a sidewall. the tires were discontinued, so I had to buy a pair of different tires to keep the axle the same, at least. the new tires are more than an inch narrower than the ones I originally bought, and they are all 265/45/20. i'm beginning to suspect the manufacturers don't stick to the tire sizes as much as they should.

 

[GT Elite]

Good to hear that you figured out what is the cause. I take it that the Conti’s are mounted on different rims from the summers. This means you have two variables to consider: the tires and the rims. To confirm that the problem is really the tire you would need to mount the Conti’s on the summer rims and see what happens then. If there is a speed difference with the Conti on a summer rim, then the problem is the Conti’s. If there is no speed difference, then the problem is with the rim.

 

[7Andrei7]

Well, the thing is that the wheels on which I have the Contis are the OEM ones that came on the car. Therefore I can rule them out because my car is 5 years old and this problem appeared only this year. Those wheels had 2 sets of summer tires on them before these Contis and I've never had problems.
The summer tires are mounted on a set of OEM Genesis G70 19" wheels which have identical specs to the OEM Stinger 19" wheels. I would say it's safe to rule out a wheel problem. It can only be the tires.

 

[GT Elite]

Well, the thing is that the wheels on which I have the Contis are the OEM ones that came on the car. Therefore I can rule them out because my car is 5 years old and this problem appeared only this year. Those wheels had 2 sets of summer tires on them before these Contis and I've never had problems.
The summer tires are mounted on a set of OEM Genesis G70 19" wheels which have identical specs to the OEM Stinger 19" wheels. I would say it's safe to rule out a wheel problem. It can only be the tires.

Agree.

 

[juan.s.03]

I have incredibly fixed it!!!
It was...... the tires. I'm not yet sure how I'll approach it with Continental but here is what I did.

As I showed before, with my winter setup, OEM spec 225/40R19 front and 255/35R19 rear with Continental TS860S on the OEM wheels I have a difference in speed read by the ABS sensors of approx 2 km/h while cruising at 80 km/h. If I floor it at higher speed, the difference between both rear wheels and both front wheels can spike up to 5-6 km/h. In those scenarios, the TC steps in and cuts power. This is the first video below.

Last night I decided to put my summer wheels on the left side, both front and read. My summers are the same OEM spec Michelin PS4 on OEM wheels. Immediately I could see that the summers (left front and back) recorded the same speed while the winters recorded a 2 km/h difference (rear front and back).

View attachment 84706View attachment 84707

Then, I put on the full summer set and went on the highway and did a few flat out accelerations from 80 to 150-160 km/h. The speed of every wheel stayed consistently within 1 km/h of each other. Needless to say, there was no TC intervention. Video below.

I'm pretty sure I've gotten to the bottom of it but here is still one pressing question: WTF Continental?!?
I will contact them and try to send out one front and one rear so they can professionally measure it and tell me what in the world is going on.
Opinions?

I'm so happy for you! Glad you fixed the issue. I never really considered the tires to be the reason behind all of this. For me, I replaced the front two tires but left the back two the same. The front left and right are each different brands and the back two share the same brand but are different from the front tires

This might be the issue for me. I assume having one brand for the front tires and having a different brand for the rear tires is okay but if the front two tires are each different brands then that might be an issue.

Curious to know what continental tells you. Keep up updated!

 

[Snicklefritz]

I have incredibly fixed it!!!
It was...... the tires. I'm not yet sure how I'll approach it with Continental but here is what I did.

As I showed before, with my winter setup, OEM spec 225/40R19 front and 255/35R19 rear with Continental TS860S on the OEM wheels I have a difference in speed read by the ABS sensors of approx 2 km/h while cruising at 80 km/h. If I floor it at higher speed, the difference between both rear wheels and both front wheels can spike up to 5-6 km/h. In those scenarios, the TC steps in and cuts power. This is the first video below.

Last night I decided to put my summer wheels on the left side, both front and read. My summers are the same OEM spec Michelin PS4 on OEM wheels. Immediately I could see that the summers (left front and back) recorded the same speed while the winters recorded a 2 km/h difference (rear front and back).

View attachment 84706View attachment 84707

Then, I put on the full summer set and went on the highway and did a few flat out accelerations from 80 to 150-160 km/h. The speed of every wheel stayed consistently within 1 km/h of each other. Needless to say, there was no TC intervention. Video below.

I'm pretty sure I've gotten to the bottom of it but here is still one pressing question: WTF Continental?!?
I will contact them and try to send out one front and one rear so they can professionally measure it and tell me what in the world is going on.
Opinions?

That is very strange. It can only be a faulty tire OD not to spec. I hope that if you're AWD that this difference in rotation hasn't harmed your AWD system. It doesn't sound like there's a problem. It's just so strange that this never happened in Sport Mode.

 

[7Andrei7]

That is very strange. It can only be a faulty tire OD not to spec. I hope that if you're AWD that this difference in rotation hasn't harmed your AWD system. It doesn't sound like there's a problem. It's just so strange that this never happened in Sport Mode.

It's RWD and I think in sport mode there is a larger wheel slip tolerance so the 5-6 km difference is not enough to trigger TC. It actually makes a lot of sense to me.

 

[7Andrei7]

I've been on summer tires for a month now and I can definitely confirm the tires were the problem. I actually just put on a brand new set of summer Goodyears Asym 6 (because my PS4s were done) and they behave exactly as the PS4s. Speed readings are within a 1km/h margin at all wheels, even at 150km/h.

In the meantime, my Continental tires are taking a journey across Europe. They first went to a local Continental office for inspection, then they were sent to a Continental factory in Western Romania. The factory also confirmed an anomaly in circumference difference so they decided to send them to the main office in Germany and try to get to the bottom of it.

I'm expecting they will fully refund me for the tires + (I hope) the cost of fitment and diagnosing the car. I spent about 150 eur just to diagnose the problem.

Will keep you guys updated in case someone runs into something like this in the future.

 

[7Andrei7]

Final update: Continental did accept my claim and sent me a new set of tires + covered the cost of fitting them on the wheels.

BUT... it appears there is still a 3cm circumference difference between the front and rear tires of the new set. It's not 4cm+ as before but I still expect to have some problems down the road. I'm thinking if I should keep them or try to sell them as 2 separate sets (to avoid problems for others) and switch to a different brand.

I believe there is a bad batch of Continental tires out there and they don't want to admit it because that would mean a recall.

In any case, I'm now on my summer Goodyears and enjoying a problem-free car. I still have 6 months to make a decision