Speed Sensitive Power Steering.

[Richard1200]

I do not drive my IS300h on motorways very much but when I do I notice at 70/75mph the steering is much heavier and slight steering corrections become a bit jerky. At 50mph it's fine.

Anybody else notice this?

I am going to ask my dealer if any adjustments are available.

[DJP]

I experienced similar 'heaviness' and discovered the tyre pressures were down at 30 psi. On the technicians advice they are at 38 psi and steering excellent.

My tyre pressure warning light came on and despite following the instructions I couldn't get t to stay off. Dropped in at Lexus and sorted.

By the way, he said I might notice a firmer ride but I haven't.

Hope this helps.

[F Sport Marcus]

I've certainly noticed a marked difference in sensitivity at speed between Sport and Normal/ECO modes.

[Richard1200]

Thanks guys. Checked my tyre pressures and they were down to 33 so put them back to 36.

Lexus Bristol confirmed there are no electronic adjustments available and that sport will be heavier than normal/Eco modes which I use so I am correct there.

No motorway journeys planned so I will have to wait to see if things are better.

[ColinBarber]

There is something very weird with the steering. At motorway speeds I can move the steering wheel very gently, about 1cm either way, which is normally enough to keep within a lane. If any more movement is required then resistance is felt on the wheel and you have to apply more pressure, at which point you oversteer and have to correct.

The best way I can describe it is that it operates like the remote touch control where it uses force when trying to move off a button.

Once you have overcome the resistance it doesn't occur again for a while. I'm not sure whether this occurs on purpose to help keep the vehicle in a straight line or something like the electric power steering is shutting down to improve economy.

[LeeG]

Hi Guys,

It sounds similar to an issue I had on my 2009 250SE/L 18 months ago. When driving in a straight line. minor corrections to keep within a lane were no problem, but a little more to change a lane it felt like resistance in the steering. A little more force to overcome the resistance and like you say it over does it. I spoke to the local dealer service manager and he said "As the steering is all 'by wire', there are motors and magnets inside. Does it feel like magnetic resistance? Try to imagine turning a small electric motor by hand."

The service manager said he would clear the steering programming and reset everything. I had it for another week and still had the issue. The steering system was then replaced under warranty. It was perfect after this.

I have not noticed anything like this on my current car.

Lee.

[DJP]

I too have continued to notice this, although less now that the tyres are at a higher pressure. Would be interesting to know if it is a safety feature or not. It's a little disconcerting, but maybe that's on purpose.

[Rabbers]

I too found the weight of the steering at motorway speeds took some getting used to when I first had the car

(surprisingly so since the previous-generation 250 I previously drove also had variable-assist steering). At 130kmh

and upwards the power assistance decreases very noticeably though by no means alarmingly. Presumably because

the heightened firmness reduces any need to overcorrect the wheel during changes of direction, I have always found

it reassuring, so much so that it has never crossed my mind that it could be anything but an aid to safety - and a very

well-calibrated one at that.

[ColinBarber]

It isn't the weight that I have a problem with, it is the intermittent excessive resistance at the centre spot I have a problem with. My front pressures where a little down, which I've now corrected, so I'll see if that makes a difference.

[DJP]

What tyre pressure have you set? I think the book says 36 but I've seen/heard anything up to 40 being used.

[ColinBarber]

What tyre pressure have you set? I think the book says 36 but I've seen/heard anything up to 40 being used.

I'm using 38 at the moment, they had dropped to around 34

[Richard1200]

I check my tyre pressures more reguarly now. Having them at 36, the correct pressure, or 38 does make a huge improvement. I do very

little motorway driving but around town I am happy with the steering.

[Rabbers]

If the excessive centre-spot resistance is related to low tyre pressure, as it might well be, I guess I was lucky to have first

had the car during a spell of cold weather. With the pressure, front and rear, set at 2.5kg/cm2=36psi as per the door-frame

sticker and manual, I was several times upset to find the pressure warning light on after frosty nights, so, on the advice of

my dealer (who had already changed a faulty sensor), I raised the pressure to 2.6kg/cm2=37psi, and have since kept it

there Winter and Summer except for temporary increases to 2.8kg/cm2=40psi for the rear tyres before long trips with a

heavy boot. Not having experienced either steering problems or, as might possibly have been expected, excessive tyre

wear, I am wondering whether pressures kept a shade over the recommended ones might not get rid of the resistance

problem.

[ColinBarber]

So I raised my pressures but it didn't really make a difference.

It appears a TSB has been issued for vehicles built before Aug 2013 for Notchy Steering feeling. Looks like the whole power steering link assembly needs to be replaced - part number is the same so it isn't a redesign, more of a manufacturing issue with the initial batch of parts.

I'll be speaking to my dealer in the next few days.

[DJP]

So I raised my pressures but it didn't really make a difference.

It appears a TSB has been issued for vehicles built before Aug 2013 for Notchy Steering feeling. Looks like the whole power steering link assembly needs to be replaced - part number is the same so it isn't a redesign, more of a manufacturing issue with the initial batch of parts.

I'll be speaking to my dealer in the next few days.

Thanks for this Colin and confirmation we aren't going mad! Sounds like a job that could take a while, I wonder if I can tie it in to loan of a NX for a couple of days :winky:

[DJP]

According to my dealer there is no TSB for the IS300 it was for the IS250. The 300 has 'stability steering' as an inbuilt safety feature as apparently so do many modern cars.

This means that as the car travels at a higher speed the steering will get tighter and feel heavier, this is done on purpose to try and minimalize any sudden steering movements at high speed to reduce the likelihood of the car flipping or spinning out of control.

That's what I've been told anyway.

Sent from my Iphone using Lexus OC

[rayaans]

According to my dealer there is no TSB for the IS300 it was for the IS250. The 300 has 'stability steering' as an inbuilt safety feature as apparently so do many modern cars.

This means that as the car travels at a higher speed the steering will get tighter and feel heavier, this is done on purpose to try and minimalize any sudden steering movements at high speed to reduce the likelihood of the car flipping or spinning out of control.

That's what I've been told anyway.

Sent from my iPhone using Lexus OC

That sounds spot on.

My RX does the same thing. At 30mph or below i can turn the steering wheel with 2 fingers. At 70mph it takes a good hand to rotate the steering wheel the same distance as at lower speeds.

Its basically what BMW call "variable steering" and is an optional extra. I think Porsche call it "servotronic" and thats an optional extra too!

[Zotto]

The steering system of IS is the same of GS, and it's quite sophisticate because it has a variable gear accordingly if working in SPORT or NORMAL mode; in sport mode you need less movement to have same steering, and in both modes of course the sensivity varies with speed. Personally I prefer in my GS the sport mode for steering, it's just a pity that setting it I have also a stiffer car for shock absorbers regulated to sporty ride.

My suggestion is to try sport mode and see if it's better for driver's preferences.

[DJP]

Thanks for that Zotto, I'll give it a try and see if it makes a difference.

Sent from my Iphone using Lexus OC

[ColinBarber]

My issue isn't anything to do with variable resistance steering. Many of my previous vehicles have had that, I know how such a system should feel. My issue is an intermittent issue, that only seems to occur once I've driven for quite a distance at high speed.

There is a TSB - I have a copy, I've attached it, and it is for both the IS250 and IS300h. I swear some dealers don't do any work and just fob off their customers.

My steering assembly has just been replaced, under warranty and obviously approved by Toyota GB so the TSB is valid.

It will probably be a week or two before I make a journey that would normally cause an issue so don't know for sure if the issue has been resolved.

CP-0044L-0314_IR.pdf

[ColinBarber]

The steering system of IS is the same of GS, and it's quite sophisticate because it has a variable gear accordingly if working in SPORT or NORMAL mode; in sport mode you need less movement to have same steering, and in both modes of course the sensivity varies with speed. Personally I prefer in my GS the sport mode for steering, it's just a pity that setting it I have also a stiffer car for shock absorbers regulated to sporty ride.

My suggestion is to try sport mode and see if it's better for driver's preferences.

The series III 450h had variable ratio steering. On the current series IV only the GS450h F Sport has it, Non F Sport 450h and all 300h do not have it.

The IS has never had it.

[DJP]

My issue isn't anything to do with variable resistance steering. Many of my previous vehicles have had that, I know how such a system should feel. My issue is an intermittent issue, that only seems to occur once I've driven for quite a distance at high speed.

There is a TSB - I have a copy, I've attached it, and it is for both the IS250 and IS300h. I swear some dealers don't do any work and just fob off their customers.

My steering assembly has just been replaced, under warranty and obviously approved by Toyota GB so the TSB is valid.

It will probably be a week or two before I make a journey that would normally cause an issue so don't know for sure if the issue has been resolved.

CP-0044L-0314_IR.pdf

Thanks Colin, that's brilliant. I was on a long journey yesterday and my passengers (wife & daughter) were accusing me of moving around the lane in a jerky way. I'll taking this up with my dealer. I bet they tell me D is still the most current software version too!!

[Zotto]

Opss sorry, I made a mistake, only GS FSport has VGRS, it is a feature that I like so much in my MY 2008 GS and I thought Lexus have put on IS earlier models.

[jobj]

On 3/19/2015 at 5:58 PM, ColinBarber said:

My issue isn't anything to do with variable resistance steering. Many of my previous vehicles have had that, I know how such a system should feel. My issue is an intermittent issue, that only seems to occur once I've driven for quite a distance at high speed.

There is a TSB - I have a copy, I've attached it, and it is for both the IS250 and IS300h. I swear some dealers don't do any work and just fob off their customers.

My steering assembly has just been replaced, under warranty and obviously approved by Toyota GB so the TSB is valid.

It will probably be a week or two before I make a journey that would normally cause an issue so don't know for sure if the issue has been resolved.

CP-0044L-0314_IR.pdf

Hi Colin, I'm from Holland and I've just bought a 2015 IS 300h. I did a first big trip to Austria and after a few hours driving I noticed the sticky steering. I googled for it and found your note on this. Unfortunately the link to the TSB is not working anymore. Could you please post that TSB again so I can download it?

Cheers, Job

[ColinBarber]

Hi Job

I just clicked on the link in my post and the PDF downloaded fine. Here is the link again:

https://www.lexusownersclub.co.uk/applications/core/interface/file/attachment.php?id=11855

 

Unfortunately I doubt this is the same issue you are experiencing as the TSB was for the first batch of vehicles produced and was fixed for all vehicles produced after August 2013.

 

 

Edited December 29, 2018 by ColinBarber
note, you need to be registered and logged in to download the attachment