RX450h First Month Review and Question

[Sandy42]

I've just joined this forum so I though I'd post my review of the 2016 RX 450h and, with luck, get an answer to a question that's been bugging me since I bought the car.

I treated myself to a 7 month old RX450h just oven a month ago after having an (excellent) IS220D for nearly 7 years.

The RX is just superb, really comfortable and easy to drive. Yes, the Nav. system is fiddly but I'm getting used to it and yes, the turning circle is humungous so I tend to avoid tight parking spaces.

I doubt that the voice recognition will ever understand my Scottish accent.

It's a pity that the Lexus software doesn't include the "voice training" routine that's included with the US version of the car though I doubt that it works quite as well as the online video I watched. Oddly shouting does help sometimes - but not always!

So far I've been averaging around 37mpg though this has been with gentle driving mostly in the city and on fast A roads.

The boot is a reasonable size though smaller than some similar sized cars. I can get my golf clubs (tour bag) and my electric trolley in there and that's all I need!

The most impressive thing I've found (so far) with the car is the BRAKE HOLD function. This holds the car when you come to a complete stop so that you don't need to keep your foot on the brake. I use this all the time though, when parking the car, it's best to turn this off otherwise the car will "lurch" slightly when you put your foot on the accelerator.

Overall then, a really impressive car with , hopefully, the really impressive reliability of a Lexus.

Now for my question which is one that my local dealership hasn't so far been able to answer:

Suppose you have parked on an incline with the car pointing down the slope. Next, suppose some thoughtless driver parks just a few inches from the front of the car (it happens!).

If you now want to move your car (backwards) how do you stop your car rolling forwards when you lift your foot off the brake? (I'm assuming the "creep" from the transmission isn't enough to compensate for the slope).

The BRAKE HOLD won't help since that only works when you are in D or S.

Maybe the HILL START-ASSIST CONTROL would be the answer but I've not been able to get that to work on my car (or, at least, not on the very slight slopes that I've tried it on).

One solution is to manually apply the PARKING BRAKE - but that just doesn't seem to be a great solution.

Anyone out there with an answer to this one? 

 

Thanks

 

 

 

 

 

[ColinBarber]

Welcome Sandy :)

Hill-start assist should work in forward or reverse (it does on the IS). Unless the slope is sufficient the hill assist won't function. I suggest you find a suitable slope and give it a test.

[Sandy42]

Thanks Colin,

On the slight incline (where I usually park) it doesn't work but usually it's OK to roll forward a bit there. Alternatively I can use the manual parking brake then wait for the display to tell me to release the brake.

I'll give your suggestion a go - after making sure there nothing in front of me!

I'm slightly surprised that it's slope dependent given the "extra brake pressing" that's needed to get the HAC operating.

Still, if that's what it takes then I've learned something today and that's got to be good.

 

[ColinBarber]

8 minutes ago, Sandy42 said:

I'm slightly surprised that it's slope dependent given the "extra brake pressing" that's needed to get the HAC operating.

Still, if that's what it takes then I've learned something today and that's got to be good.

 

I assumed you have a forth generation RX (new shape) and also assumed that the hill assist is now fully automatic on the RX as it is with the IS and current Toyota vehicles. Do you still have to press down hard and get a beep confirmation?

[rayaans]

Mine doesn't roll forward even on moderate inclines

Brake hold was activated on my 3RX by pressing the brake down all the way for until a beep was heard and the slip indicator flashed. It'll hold for 2 seconds and then let go.

I believe it's automatic on the 2016 RX which would explain why it doesn't roll unless the incline is steep

[ColinBarber]

6 minutes ago, rayaans said:

I believe it's automatic on the 2016 RX which would explain why it doesn't roll unless the incline is steep

If it is automatic then it shouldn't roll at all, doesn't matter how steep the incline is as the system will hold the brakes for 2 seconds.

[rayaans]

Just now, ColinBarber said:

If it is automatic then it shouldn't roll at all, doesn't matter how steep the incline is as the system will hold the brakes for 2 seconds.

Well I'm just assuming. It hasn't rolled at all but I haven't tried it on a steep hill to confirm

[Sandy42]

Mmmm... Yes mine is the 4th generation. The manual doesn't say it's automatic but the text from the manual would suggest that it is:

Operating conditions of hill-start assist control
When the following four conditions are met, the hill-start assist control will operate:
● The shift lever is in a position other than P or N (when starting off forward/backward on
an upward incline).
● The vehicle is stopped.
● The accelerator pedal is not depressed.
● The parking brake is not engaged

So maybe the online videos I've been watching about depressing the brake pedal don't apply to my car though it definitely rolls forward on a the slight downward incline where I usually park as soon as I engage R and release the brake pedal (and, I think, before my 2 seconds are up).

Looks like next week will be one of experimenting. I don't like the look of the UPWARD INCLINE in the 1st line of the instruction though - what about my DOWNWARD INCLINE??

 

 

[Sandy42]

Oh - one more thing.

I read somewhere online that there aren't any beeps or flashing slip indicator on the latest RX version when HAC is operating. 

Apparently someone was told this by their local Lexus dealer.

That seems a bit of an odd thing to do - but is it true?

[ColinBarber]

35 minutes ago, Sandy42 said:

Mmmm... Yes mine is the 4th generation. The manual doesn't say it's automatic but the text from the manual would suggest that it is:

Operating conditions of hill-start assist control
When the following four conditions are met, the hill-start assist control will operate:
● The shift lever is in a position other than P or N (when starting off forward/backward on
an upward incline).
● The vehicle is stopped.
● The accelerator pedal is not depressed.
● The parking brake is not engaged

So maybe the online videos I've been watching about depressing the brake pedal don't apply to my car though it definitely rolls forward on a the slight downward incline where I usually park as soon as I engage R and release the brake pedal (and, I think, before my 2 seconds are up).

Looks like next week will be one of experimenting. I don't like the look of the UPWARD INCLINE in the 1st line of the instruction though - what about my DOWNWARD INCLINE??

 

 

That's the same wording as the IS manual, so yes this is fully automatic.

The way I read this is if you are in reverse then it is an upwards incline when the vehicle is pointing downwards? I'm sure it works, my father's drive is steep and my old RX used to move forwards when reversing up, but I don't remember my IS ever doing it.

[Sandy42]

Thanks again Colin.

That's two things I've learned today.

I must not  take the English language so literally!!

[ColinBarber]

Tested hill-start assist today on a car park ramp.

Going up - stopped, released the brakes and the vehicle stayed still for just over 2 seconds at which point it started to move back slowly as the brakes were released.

Going down - stopped, selected reverse, released the brakes and the vehicle stayed still for just over 2 seconds at which point it moved a couple of inches forwards and then the was held by the hybrid system until I pressed the throttle and it moved backwards up the slope.

 

[Sandy42]

Thanks again Colin.

The middle of Edinburgh is a bit short of traffic free hills so I'll need to get out of town to do my tests properly.

Probably I'll wait till the weekend.

I'll report back when they're done.

[Sandy42]

So - just done my testing on a fairly steep slope with the car pointing down the hill.

Stopped the car, foot on the brake, shifted to R, foot off the brake and the car didn't roll forward.

BUT it didn't start to roll after 2 seconds either and, in fact, it didn't roll forward after 30 seconds and more. So, I was confused. Maybe the hybrid system was holding it.

I then put my foot back on the brake and shifted to N then released the brake. The car rolled down the hill fairly quickly.

I did these tests a few times with the same result.

I didn't bother doing a test with the car pointing up the hill since I know the BRAKE HOLD function would work just fine when in D.

In summary then:

Probably the HILL-START ASSIST CONTROL works OK but it's not something I'm going to rely on.

Whether it works or not seems to be slope dependent.

I do think that's it's a Lexus mistake not to provide some visual or audible indication that the HAC has been set as they did for the earlier RX versions.

Think I'll stick to applying the parking brake manually in situations where I need to.

PS I'm now up to just over 40mpg. Of course, since I've retired, I've no need to go anywhere in a hurry!