EV mode button

Navnan2 · May 10, 2021

Can anybody advise what this button is for? Every time I press it thinking I can drive just in electric mode it just tells me EV is not available or not enough range or something. I guess there is something in the manual about this but I blowed if I can find anything. Thanks!

NemesisUK · May 10, 2021

I'm guessing you have the UX250h variant?

In which case the EV will try and force the car into electric only mode but excessive throttle will cancel it, excessive speed will cancel it, low traction Battery charge will cancel it, or not allow it at all..

Navnan2 · May 10, 2021

20 minutes ago, NemesisUK said:

I'm guessing you have the UX250h variant?

In which case the EV will try and force the car into electric only mode but excessive throttle will cancel it, excessive speed will cancel it, low traction battery charge will cancel it, or not allow it at all..

Hello Peter, yes that's my vehicle. I've never been able to enable this mode however careful I have been driving unless it only works at such a slow speed its of no use. The range thing perplexes me, how does it know how far I am going to drive? Its not the end of the world but seems a pointless option. My neighbour's Outlander hybrid seems happy to be driven in this mode. Thanks for your reply.

-Error- · May 10, 2021

The EV mode will require a lot of conditions to be just right, it will not engage if:
●The temperature of the hybrid system is high. The vehicle has been left in the sun, driven on a hill, driven at high speeds, etc.

●The temperature of the hybrid system is low. The vehicle has been left in temperatures lower than about 0 °C for a long period of time, etc.

●The gasoline engine is warming up.

●The hybrid Battery (traction battery) is low. The remaining Battery level indicated in the “Energy Monitor” display is low.

●Vehicle speed is high.

●The accelerator pedal is depressed firmly or the vehicle is on a hill, etc.

●The windshield defogger is in use

A lot of times it's A/C that catches people out. Try these things out, if a problem persists there might be another problem which would require diagnostics

NemesisUK · May 10, 2021

Page 260 of the online owner's handbook details EV mode.

If it's anything like my RC300H then speed must be below 20-25mph and on a very light throttle, the slightest incline will cancel the mode. Range is also limited, perhaps 300m cold and 1-2km warm (traction Battery temp)

I only use the EV mode to silently pull out of my drive in the early mornings and then the EV button must be pressed before the petrol engine fires, perhaps 5-10sec after READY.

I've not found a/c settings make any difference, the engine will fire up to provide cabin warmth, this doesn't always cancel EV mode. I've seen the energy monitor show only the traction Battery driving the wheels even when the engine is running, this doesn't last long though!

It must be remembered the Lexus hybrid is not designed as an electric drive optimised vehicle, more a Stop-Start system on steroids.

-Error- · May 10, 2021

Very interesting NemesisUK, do you happen to know what generation the RC hybrid drive is? I long for the ability to use the EV in the mornings but it will only ever engage after a few minutes of petrol driving, regardless of season/temp. Unless I've already pre-heated the petrol engine, the EV will not start the car. And the EV mode will only stay on until 30mph, although the electric drivetrain will actually work until 45mph.

With regards to A/C I found it that the EV mode will cut off much sooner if it's switched on (especially the demister), tried it in my GS as well as the latest RX whilst waiting at Dover ferries. The Battery charge status seems to have shown higher bars when cutting off the EV mode if the A/C was still on in both vehicles.

The UX is a 4th gen and the EV can actually go into much higher speeds (I remember seeing at least 60mph EV cruise), wish I've tested its top speed when I had one. It will also cover quite a good distance on batteries, it's miles over any other Lexus Hybrid I've driven before. I've scheduled to have the electric one as courtesy car during my next service as I'm quite excited to see what Toyota has managed to come up with.

NemesisUK · May 10, 2021

My 2019 RC is one generation behind the UX. My previous RC (pre-facelift 2016 model) was even less able in EV mode but I believe Lexus upgraded the hybrid control system between the two models, there is a marked improvement (higher speed/acceleration, longer running, easier cold running) in the newer model but they behave basically the same.

I remember driving a UX when mine was in for service and noted the higher speeds and higher acceleration available in EV mode.

ColinBarber · May 10, 2021

4 hours ago, Navnan2 said:

Can anybody advise what this button is for? Every time I press it thinking I can drive just in electric mode it just tells me EV is not available or not enough range or something. I guess there is something in the manual about this but I blowed if I can find anything. Thanks!

It is for driving in electric mode but it isn't something you should normally do is it is less economical to do so compared to the hybrid system determining when it is most appropriate to use electric mode or not.

It's really just there to allow you to move your vehicle off a driveway rather than having the petrol engine start up, or to cut emissions as you drive slowly past a school. But I find it almost useless on the UX as it is nearly always unavailable, even when first starting before the petrol engine fires up - on other hybrid models it is more usable.

Navnan2 · May 11, 2021

13 hours ago, ColinBarber said:

It is for driving in electric mode but it isn't something you should normally do is it is less economical to do so compared to the hybrid system determining when it is most appropriate to use electric mode or not.

It's really just there to allow you to move your vehicle off a driveway rather than having the petrol engine start up, or to cut emissions as you drive slowly past a school. But I find it almost useless on the UX as it is nearly always unavailable, even when first starting before the petrol engine fires up - on other hybrid models it is more usable.

Thanks Colin and others for there responses. I get it now and will ignore the feature. Just moving the car out the drive in electric as an example seems pointless and I invariably drive slow past schools and the EV mode is normally engaged automatically anyway. Cheers, Barry

paulrnx · May 11, 2021

34 minutes ago, Navnan2 said:

Thanks Colin and others for there responses. I get it now and will ignore the feature. Just moving the car out the drive in electric as an example seems pointless and I invariably drive slow past schools and the EV mode is normally engaged automatically anyway. Cheers, Barry

I use it on my road and I also use it in the village where I live especially when entering. I also use it when in carparks and when in traffic. It keeps the ICE off more of the time from what I experience. I see it as no different to using Sport Mode whenever I need a bit more response from the drivetrain. Equally fine to leave it as it is and let the car decide what is best at any particular time though if desired.

ColinBarber · May 11, 2021

6 hours ago, paulrnx said:

It keeps the ICE off more of the time from what I experience.

Confused by this. EV mode means the ICE isn't used at all.

paulrnx · May 12, 2021

23 hours ago, ColinBarber said:

Confused by this. EV mode means the ICE isn't used at all.

The ICE will cut in when the car thinks it needs to even in EV mode when the traction batteries run low or some other condition forces this such as a hefty press of the accelerator or Battery conditioning etc. My experience is that manually selecting EV mode, as opposed to the car dropping into EV mode itself, appears to give a longer period of EV running as long as the speed is kept below 30 (because manual EV mode will always drop out at 30+). Manually selecting EV mode appears to allow a firmer press of the accelerator without triggering the ICE to come on. Ordinarily the lightest touch on the accelerator in normal running will trigger the ICE to come on as soon as the needle goes into the power segment. I’ve found the behaviour and EV power delivery to be different when manually selecting EV mode. Might be me but this is my 4th hybrid (2 x IS and 2 x NX). I’d be interested to hear if others see the same. Obviously you can’t mash the accelerator because this always triggers the ICE.

ColinBarber · May 12, 2021

1 minute ago, paulrnx said:

The ICE will cut in when the car thinks it needs to even in EV mode when the traction batteries run low or some other condition forces this such as a hefty press of the accelerator or battery conditioning etc.

Correct, at which point it cancels EV drive mode - there is no ICE whilst the vehicle is in EV drive mode.

EV drive mode and the ease at which it is cancelled varies a bit between vehicles. The IS300h when cold for example is limited to a max speed of 19 mph and only the very gentlest of throttle application will stop it from being cancelled. Once warmed up you can get to 28 mph (around 31 mph on the speedo) and apply a bit more throttle.

If you keep below the max. speed and limit the amount of throttle then certainly you will remain running in EV longer than if the hybrid system engaged automatic EV mode - that's because the driver has explicitly called for EV so it will only cancel when it has to, whereas in automatic mode the vehicle will come out of EV mode when it is more economical to do so (hence the reason why forced EV drive mode is less economical than leaving the hybrid system to look after itself).

paulrnx · May 12, 2021

25 minutes ago, ColinBarber said:

Correct, at which point it cancels EV drive mode - there is no ICE whilst the vehicle is in EV drive mode.

EV drive mode and the ease at which it is cancelled varies a bit between vehicles. The IS300h when cold for example is limited to a max speed of 19 mph and only the very gentlest of throttle application will stop it from being cancelled. Once warmed up you can get to 28 mph (around 31 mph on the speedo) and apply a bit more throttle.

If you keep below the max. speed and limit the amount of throttle then certainly you will remain running in EV longer than if the hybrid system engaged automatic EV mode - that's because the driver has explicitly called for EV so it will only cancel when it has to, whereas in automatic mode the vehicle will come out of EV mode when it is more economical to do so (hence the reason why forced EV drive mode is less economical than leaving the hybrid system to look after itself).

Agreed. Not just about economy though for me at least. I like driving in EV mode under certain conditions. If it was purely about economy I doubt I’d be driving a Lexus hybrid to be honest.

cur666 · May 13, 2021

15 hours ago, ColinBarber said:

Correct, at which point it cancels EV drive mode - there is no ICE whilst the vehicle is in EV drive mode.

EV drive mode and the ease at which it is cancelled varies a bit between vehicles. The IS300h when cold for example is limited to a max speed of 19 mph and only the very gentlest of throttle application will stop it from being cancelled. Once warmed up you can get to 28 mph (around 31 mph on the speedo) and apply a bit more throttle.

If you keep below the max. speed and limit the amount of throttle then certainly you will remain running in EV longer than if the hybrid system engaged automatic EV mode - that's because the driver has explicitly called for EV so it will only cancel when it has to, whereas in automatic mode the vehicle will come out of EV mode when it is more economical to do so (hence the reason why forced EV drive mode is less economical than leaving the hybrid system to look after itself).

I have a UX....ungraded from a NX :). What you said above relates to the NX....the UX has 4th generation hybrid....drives faster and longer without ice. This is the UX portion of this forum?

ColinBarber · May 13, 2021

10 hours ago, cur666 said:

I have a UX....ungraded from a NX :). What you said above relates to the NX....the UX has 4th generation hybrid....drives faster and longer without ice.

It will go faster and longer in EV mode (up to 44 mph in AWD and 71 mph in FWD) but not in EV drive mode, which is roughly the same and seemingly unavailable for much longer periods of time compared to the NX.

The 4th gen hybrid is just marketing to make it sound more advanced. There have really only been 3 hybrid system generations for Lexus, which match the last three Prius generations, no Lexus hybrid existed which used the original Prius technology. If we are just taking about minor tweaks then there are 6 or 7 generations.