Solved : Transistion to S4 without idle check.

This is a technique that I've been using fairly often lately and it works really well. Ken1784 gave me this tip ages ago in another thread, but I get the feeling that a lot of people still don't know about it. That's why I'm making a specific thread for this so it will be easy to search on.

The technique is simple, once you've warmed up just turn the car off (one second is enough) then turn it immediately back on.

That's it. At first it doesn't sound very useful because you have to stop the car anyway to turn it off. So why is this any better than stopping for the idle check?

Well there are two reasons why it's better. One reason is that's it's a little bit quicker. The idle check can take up to ten seconds whereas you can turn it off and back on in about four seconds (maybe even three if you're quick).

That's not the main reason however. In fact if I do have to stop while the car is idling then I'll usually just let it do the idle check anyway. The real advantage of this "off/on" method is you can do it after gliding to a stop from above 55 km/h (34 MPH) while then engine is NOT running.

You see my problem is not so much that my trips don't give me the opportunity to stop (traffic lights for example). The problem is more that I mostly manage to glide up to these stops from above 55 km/h, so the engine is already off and therefore no idle check occurs. With the "off/on" technique I can just flick it off and back on in about 3 to 4 seconds, even if stopped at lights without the engine running.

Warning : Never try to turn the engine off while the car is still rolling. Above about 6 MPH it will just go into neutral so it wont turn off but no harm done. At about 6 MPH or below however it really will turn off, but it will slam it into "park" while doing so which gives the transmission quite a shudder. So always be at a dead stop before trying this.

 

Yep that's it. Dont forget that you still have to put it back into drive though.

Yes that's *exactly* right 2009Prius. In fact this technique first came to my attention for precisely that reason. In summer I noticed that I was sometimes getting to S4 even though I was 100% certain that I'd never been through the idle check! It really puzzled me and I couldn't figure out why, but eventually ken1784 clued me in to the fact that it would go straight into S4 at start up if the coolant temperature was already warm enough. Suddenly it all made sense and I realized that every time that I'd "mysterious" entered S4 that the car had been driven fairly recently and it was warm weather.

 

It depends on the outside temperature and how hard you're driving. It's usually about 5 minutes or less for me.

 

I guess it would, but I cant say whether or not it will be detrimental to the engine to bypass the normal warm-up cycle like that. I'd be a bit wary.

 

Yes, that's why I credited Ken in the first line of the first post.

It's just that I noticed that many people don't seem to know about it. Also I think many people don't realize how useful it can be.

Edit: Well I just checked and it was only 4 months ago (start of summer down under) when I posted the question about my mysteriously entering S4 without idle check and I can tell you that nobody knew about it then. The thread went on for several pages and everybody thought I was imagining it or that I had driven so slow at some point that it had done the idle check without me realizing it etc etc. Even some of the most senior members that normally have all the answers couldn't help me. Eventual Ken gave me the low down and it seemed as though he was the only one clued into this. But since his reply was a brief one "buried" on the third page of my thread I think that many people didn't see it and that most still don't know about it. This S4 problem is such a FAQ that I wanted a dedicated thread for it with a title that could be easily searched.

 

Yeah that's my problem too. And even when I deliberately try to plan a stop from below 34 MPH so that it can do the check I often get the lights go green (or another car comes up behind me at a stop sign) and I have to move off before the idle check is complete. It can be very frustrating.

Yes the speed is a big advantage. I find that if I'm at the front of the queue at a red light then you can see what the lights are doing for the other direction so you always have time to do the "off/on" trick (because the time that the lights take to go amber - red in the other direction is actually all the time you need!)

Also if you are half a dozen cars back in the queue then you still have time, because even if the lights go green just as you start the procedure it's always going to be at least 2 to 3 seconds before the cars in front of you get going. So even then you're probably only going hold up the line for about 1 second worst case.

 

Ken, I've been experimenting with it over the past few months at traffic lights and stop signs and I've found you can basically do it as quickly as it will physically let you (about 3 seconds for the complete cycle) and it still works.

I do agree however that most electrical and computer related equipment prefers to be switched off for at least several seconds before the power is cycled. From my tests though I'm pretty sure that the "quick as possible" method is doing it no harm. Nothing that I've observed anyway.

 

Because getting the car into "hybrid stage 4" is very desirable. See http://www.techno-fandom.org/~hobbit/cars/five-stages.txt