What Is The “s” Slot For On The Gearbox?

PhilipK · July 14, 2015

I am much more used to Manual transmissions (this is only my second ever Automatic that I’ve owned), so please bear with a basic question.

I understand that the “manual” override on the IS250 gearbox doesn’t actually change gears, but only constrains the highest gear which the car can choose. What I don’t understand is why the additional “S” slot is needed on the gear lever, given that you can change the setting using the paddles while the car is in “D”.

Let’s say I’m in 6^th, but going steeply downhill and want some more engine braking, so I decide to select 4^th gear (or, to be pedantic, only allow the car to choose 1^st, 2^nd, 3^rd or 4^th gear, but not 5^th or 6^th).

There are 3 ways that I can do this:

Put the lever in “S” and push it in the “-“ direction twice
Put the lever into “S” and use the “-“ paddle twice
Leave the lever in “D” and use the “-“ paddle twice

Is there any difference between these 3 methods (and if not, why bother having the “S” slot?)

milleplod · July 14, 2015

On my 56-plate 250, I think the paddles only work when the gearlever is over in the 'S' slot. If its in 'D' and I move it to 'S', it automatically drops to 4th gear, assuming it was in 6th or 5th when in 'D'. I've also got a little button marked 'change lock', or similar, that I assume will lock it in whatever gear its in when I press it....but I could have got that wrong as I've not read up on it! Are later models different in respect of the paddles/'S' slot I wonder?

Pete

PhilipK · July 14, 2015

As far as I know, the "Shift Lock" button (which I guess is what you're referring to) is an override which allows to move the shift lever out of the "P" position without the engine running/foot brake on - for example, if you have a dead Battery and need to push the car, or if the feed which tells the computer that the foot brake is on is broken. I don't think that it has anything to do with which gear range the car selects.

I don't know whether the pre- and post-facelift cars are different in terms of using the paddles when the car is in "D", though. Hmmm.

milleplod · July 14, 2015

Aahh, right! Not got the car here at the moment to have a look - I did wonder what the button was for!

I'm sure I've read on here somewhere that later cars are different - that they didn't have the 'S' slot though. But I'm easily confused!

Pete

noby76 · July 14, 2015

I read a while back on the US forums this was more related to IS-F that when in D and you use the paddle shifters to drop gears the transmissions ECU will revert back to the maximum gear which in your case (6th) after a couple of seconds of not using the paddle shifters but when in S and you drop down gears say from 6th to 4th the ECU will limit the maximum gear allowed to 4th in other words 5th and 6th will be cancelled out making only 1,2 3 and 4th available for use. I think S mode sharpens things up further when used with ECT PWR button compared to when in D

johnatg · July 14, 2015

The paddles only work in 'S' on early (pre-2009?) cars. They work in 'D' or 'S' on later ones.

'S' is 'Sports' mode - the box will change down earler (eg when braking into a corner) and hold on to lower gears for longer when accelerating than in 'D'.

You get pretty much the same effect with 'ECT Power' selected on the switch - not quite the same but it's pretty confusing to have so many options. Maybe different design teams were competing to see who could come up with the best solution for 'sports' driving and they just decided to chuck the lot in!

Jamesf1 · July 14, 2015

I thought s stood for sequential. Sports mode is ect pwr setting. The difference between paddles and s on the lever is in my experience, use paddles without s it drops back into normal auto mode after a short while if you don't pull a paddle (the number displayed showing highest gear allowed disappears) and full auto resumes. Put the lever into s and it sticks with highest gear selected unti you move the lever back to d.

johnatg · July 15, 2015

Hmm - that's somewhat different from operation on early cars. On them, put it in S and it stays there, but it limits highest gear to 4 unless you 'paddle up'. It still works in full auto except that you can select the highest gear the box will go to with the paddles. That effectively means you can change up manually as you accelerate, taking it to high revs in each gear before using the up paddle to go to the next one. And you can change down as you approach a corner to be ready to accelerate out.

ECT PWR makes it more likely to change down as you approach a corner but you have less precise control. And it hangs on to lower gears for longer during acceleration. You can of course use both S and ECT PWR together.

Jamesf1 · July 15, 2015

My explanation may have been too vague.

S mode= set a limit for highest gear full auto Upto that gear.

Set s mode with the stick, and that mode is used until the stick is put back into d, regardless of paddle use.

Set s mode using the paddles(stick stays in d) and s mode is temporary. Full gear range is restored automatically if you come to a complete stop, select 6 as the highest gear allowed or don't operate a paddle for a set period.

You can also override s mode if activated by paddle rather than stick by pulling the + paddle for a couple of seconds.(stick in d)

S mode isn't intended as a sports mode as such (imho) but by limiting the highest gear it is useful for planned overtakes As it allows the engine to rev. The handbook only refers to s mode to allow engine braking to be increased where necessary.

I find using the paddles to "manually" change gear results in a less refined gear change than full auto. The ISF had an m mode in place of s, which is a true manual gear change mode. In a 250 the paddle isn't directly instructing a gear change, it's setting the highest gear allowed parameter.

milleplod · July 15, 2015

"........In a 250 the paddle isn't directly instructing a gear change, it's setting the highest gear allowed parameter".

But surely the paddle does instruct a change when you request a lower gear? It changes down to it immediately, very handy in 'spirited' driving on twisty bits I find!

Pete

ColinBarber · July 15, 2015

If you request a lower gear than the transmission is currently in then yes it will force a change - provided it won't take the engine over the rev limit.

milleplod · July 16, 2015

I've just had a nicely spirited blast in my 250. The paddles don't do anything when the gearstick's in 'D', as expected....but they sure make for a fun drive in 'S' with 'ECT PWR' switched on!

Pete

Jamesf1 · July 16, 2015

I've just had a nicely spirited blast in my 250. The paddles don't do anything when the gearstick's in 'D', as expected....but they sure make for a fun drive in 'S' with 'ECT PWR' switched on!

Pete

you need to pull on the "- "paddle for a second or 2 to activate them in D. But my car is post facelift..

BillNick · July 17, 2015

Last night (first journey in my IS250) I was in D doing 70mph and i went into S and it was only in 4th which of course raised the revs dramatically.

Then I pulled to some lights some time later. Switched into S again this time stationary and it was still in 4th???

This leads me to think it S mode stays in the gear you was last in when using it??? No? Seem silly so I am probably wrong.

milleplod · July 17, 2015

I think you'll find that 4 is the highest gear it will select...so, when you're stationary in 'S', although the display shows '4', the gearbox will have selected '1' and will then go up as far as '4'.....unless you instruct it differently while stationary via the paddles.

Pete

Jamesf1 · July 17, 2015

Last night (first journey in my IS250) I was in D doing 70mph and i went into S and it was only in 4th which of course raised the revs dramatically.

Then I pulled to some lights some time later. Switched into S again this time stationary and it was still in 4th???

This leads me to think it S mode stays in the gear you was last in when using it??? No? Seem silly so I am probably wrong.

by default it always goes into 4 or 5 depending on speed at the time. It can default to 2 or 3 if you have been gently plodding around before hand (according to the handbook). Ive only ever seen mine default to 4 or 5 - mostly 4

johnatg · July 17, 2015

When you switch to 'S' the box automatically selects highest gear available as 4. If you were stationary, the actual gear you were in (1st actually) would not be shown in the top 'strip' display (if you have current gear displayed there as opposed to outside temp or average fuel consumption or whatever) but the red LED indication of the highest available will be 4.