GR Yaris POWER STEERING FAILS mid turn on the Nürburgring

Dragos_DreS

Dragos_DreS

Absorbed member
May 18, 2023
36
62
18
Hi Everyone,

So today I did my first proper laps on the TE37’s with the Yokohama Ao52 (255).

On my first lap, I set the tire pressure to 2.10 BAR just to get a bit of heat into them and after passing 3 crashes, the Ring temporarily closed or a little while.

As it reopened 30 mins later, I had to do another warmup lap and I got the tire pressure this time to 2.35BAR which I dropped down to 2.05BAR.

Here we GO, the tires are at the right temperature and grip!

I could finally push the car hard and for a little while I was amazed at how well the car drove on the new tires.

When I got to the second left on (Metzgesfeld), boom 95% of my power steering, gone. And by gone, I mean gone right in the middle of the turn.
I fought my wheel to the left as hard as I could but at some point, I thought it was safer to just hop onto the grass just in case the wheel stayed locked and I couldn’t steer to the right afterwards.

Can anyone tell me what happened?

I heard that the wider tires, plus the extra grip from the Ao52’s might have overloaded the electrical steering motor? Can that be?

Pretty scary if the car is able to turn at high speeds but the steering fails mid turn.

Any advice would be greatly appreciated.

nur_01.webp
 
  • Wow
Reactions: Kaxe, Duke, DobiLux and 2 others
Crikey, that's a bit worrying. I hope Toyota didn't just fit the same assist motor as in the cooking Yaris because I can easily understand why that might struggle.
 
  • Like
Reactions: DobiLux and GRandemakina
I think MagnusT on the old forum already reported about that early on.

In the vid they mention reducing caster and having a larger lever on the steering rod to reduce loads (possible with Verkline).

To that I add that NOT running low ET but rather stock ET on the rims probably helps too.
 
  • Like
Reactions: tonic, Hini, Ecsrobin and 2 others
Greenthumb said:
Yes. You not the first and not the last.

The car, or rather the steering, doesn't like fat semis.

You're German, so you can watch the video. Start at minute 9:00

Click to expand...

First, a big thank you for this video!

It pointed me in the right direction even though there is no solution. I will call these guys and see if they are able to tell me more about it.

Under the youtube comments, this is the closest thing I found..

Screen Shot 2023-07-21 at 11.05.35.webp
 
  • Wow
  • Like
Reactions: DobiLux, Michael Knight and Onehp
Hi. I'm the one replied to 55parts on Youtube. I also have experienced this "feature" a few times and it's not pleasant.

This year I'm on street tires again and are not experienced it once. So probaly just the servo not keeping up on wide semis or under high loads in the corner. As mentioned in the YouTube post reducing caster helps, (beware that your tires will wear on the inside if you drive with less caster🙄.... not really its a joke of course but I had a bit of a debate on this topic)
Less camber and less stickier tires will probably help aswell but whereas the fun in that?

I hade this primarily during trailbraking into a corner and have the feeling its connected to braking aswell? Therefore I reduced antidive and that helped in my case.

Are you on stock alignment still?
As mentioned as I removed the ARB and it disappeared. No explanation to why but it did.
 
  • Like
  • Wow
Reactions: DobiLux, Orion, Duke and 2 others
I can say that I experienced it as well on my first track day with everything stock (including the Michelin 4s) and the car just over 3k kilometers.
It was a brief 10x resistance to the wheel while doing something stupid just to see how the car would react. I don't remember what exactly but I was also shocked that it felt that way. Since then I've done several track days with Nankangs AR-1 still 225 without any issues.
 
  • Wow
Reactions: DobiLux
In the old days that would tell me it was a power steering pump capacity issue, but I’m not sure how that translates into EPAS?

Voltage dip, maybe? Beef-up the cables to the motor =problem solved?
 
  • Like
Reactions: DobiLux, DrSetup and Onehp
Duke said:
In the old days that would tell me it was a power steering pump capacity issue, but I’m not sure how that translates into EPAS?

Voltage dip, maybe? Beef-up the cables to the motor =problem solved?
Click to expand...
Just thinking our loud, but I noticed the EPAS calibrates itself straight after reconnecting the battery. If having this issue after switching tyres, maybe a reset might help? I talked to MagnusT and he said his issues disappeared after a dealer ecu update, maybe as simple as an EPAS reset?
 
  • Like
Reactions: Orion, DobiLux and Duke
DrSetup said:
Hi. I'm the one replied to 55parts on Youtube. I also have experienced this "feature" a few times and it's not pleasant.

This year I'm on street tires again and are not experienced it once. So probaly just the servo not keeping up on wide semis or under high loads in the corner. As mentioned in the YouTube post reducing caster helps, (beware that your tires will wear on the inside if you drive with less caster🙄.... not really its a joke of course but I had a bit of a debate on this topic)
Less camber and less stickier tires will probably help aswell but whereas the fun in that?

I hade this primarily during trailbraking into a corner and have the feeling its connected to braking aswell? Therefore I reduced antidive and that helped in my case.

Are you on stock alignment still?
As mentioned as I removed the ARB and it disappeared. No explanation to why but it did.
Click to expand...

I have a question for you and for everyone that has had this issue.

From how some people are describing this issue, it sounds a bit like it isn’t that big of a deal.

Basically, mid turn the power steering turns off and you just have to pull a little harder on the wheel, same as on an older car without power steering.

For me it felt like a 1-1.5sec full on steering wheel lock that allowed for a little bit of steering but only under my full force.
Imagine a locked steering wheel where if you pull on as hard as you can, you will move it but only a little bit.

Did you guys just lose power steering but you could still steer just fine, or did it feel like your wheel was locked?

- - -

Regarding my setup, I do not know all the details unfortunately. Plus, we changed the alignment and balance a few times already.
The car was done my 24/7 Performance. These guys specialize in suspension setups for the Nürburgring.
If it wasn’t for this steering lock issue, I can easily say that the car drives like a dream.

And you are right, I guess I could change the setup to be better suited for this issue but where is the fun in driving a track car with an almost street setup.

The car has quite a few upgrades that I don’t want to bore you guys with but here are some that are related to this post:

- TE37's in 18x9,5 +45 (with a 15mm spacer in the front and 7mm spacer in the rear),
- Yokohama Ao52 (255) tires,
- Moton 3way suspension,
- brake pads + lines
- half roll cage
- the lower motor mount

One question! What does the car drive like without the Anti-Roll bar?
 
Last edited:
  • Like
Reactions: DobiLux and DrSetup
Onehp said:
Just thinking our loud, but I noticed the EPAS calibrates itself straight after reconnecting the battery. If having this issue after switching tyres, maybe a reset might help? I talked to MagnusT and he said his issues disappeared after a dealer ecu update, maybe as simple as an EPAS reset?
Click to expand...
That would be crazy if it works. I guess at this point I have nothing to lose.

Restarting my computer fixes 90% of the issues.. why not try it on the Yaris. 😅👍
 
  • Haha
  • Like
Reactions: DobiLux, DrSetup and Onehp
Onehp said:
What rate are your front springs on your coilovers? As I imagine they already reduce most of the roll anyway...
Click to expand...
On my setup I'm running some pretty hardcore coilovers. I will ask my shop what they think of getting rid of the ARB and post their answer on here next week.
 
  • Like
Reactions: DrSetup
Dragos_DreS said:
I have a question for you and for everyone that has had this issue.

From how some people are describing this issue, it sounds a bit like it isn’t that big of a deal.

Basically, mid turn the power steering turns off and you just have to pull a little harder on the wheel, same as on an older car without power steering.

For me it felt like a 1-1.5sec full on steering wheel lock that allowed for a little bit of steering but only under my full force.
Imagine a locked steering wheel where if you pull on as hard as you can, you will move it but only a little bit.

Did you guys just lose power steering but you could still steer just fine, or did it feel like your wheel was locked?

- - -

Regarding my setup, I do not know all the details unfortunately. Plus, we changed the alignment and balance a few times already.
The car was done my 24/7 Performance. These guys specialize in suspension setups for the Nürburgring.
If it wasn’t for this steering lock issue, I can easily say that the car drives like a dream.

And you are right, I guess I could change the setup to be better suited for this issue but where is the fun in driving a track car with an almost street setup.

The car has quite a few upgrades that I don’t want to bore you guys with but here are some that are related to this post:

- TE37's in 18x9,5 +45 (with a 15mm spacer in the front and 7mm spacer in the rear),
- Yokohama Ao52 (255) tires,
- Moton 3way suspension,
- brake pads + lines
- half roll cage
- the lower motor mount

One question! What does the car drive like without the Anti-Roll bar?
Click to expand...
Sounds like a fun build.

The few times I had it was mostly during trailbraking. Definitely feels like the steering "locks up" but it's possible to steer with a lot of effort.

As my suspension is hard it's not a big diffrence to drive without arb. I needed better turn-in and less understeer so tried to uncouple one side to get both front wheels on the ground at the same time and it worked. Swedish tracks are small and tight so need to change directions fast more than be stable on long fast sweepers.
 
  • Like
Reactions: Dragos_DreS and GRandemakina
I visited the local track today with stock suspension and cup2 and power steering loss was easily noted every time in ”fast” right hander where you brake into.

It starts when you trail brake into corner and front wheels get ’loaded’. Disappeares after 1s.

Thought of maybe raising an issue of this as it happens with stock suspension and wheels.
 
  • Like
Reactions: Orion, DobiLux and MarkoS
You must log in or register to reply here.
Top Bottom
Back