C.C. overspeeding down hill. Audio not muting for Sat Nav

[Lesfac]

I have come to my RX450h from a Kia Sorento KX4 that had most of the bells and whistles of the RX.

I cant help comparing and I am a bit disapointed that the cruise control allows the RX to run away down hill whereas the Sorento didnt.

Also the audio system doesnt mute the audio to allow the Sat nav instructions to be heard. Again the Sorento did this.

I am hoping some one can tell me these things can be dialed in some how.

Les

[Las Palmas]

Diesel engines are better reducing speed downhill. A hybrid needs to engage brakes. A CT has a B position in gear selector, that is meant to reduce speed downhill, do not know how RX is taking care of that.

Anyway, hybrid cars are not for mountain areas. On the way up engine is using fuel constant and on the way down hybrid Battery is full after a few minutes meaning braking power is wasted turning to heat.

[NemesisUK]

46 minutes ago, Las Palmas said:

hybrid cars are not for mountain areas.

Au contraire, I think they are perfectly suited to hilly. mountainous roads. Battery assistance on the way up and regenerative braking on the way down.

As for the cruise control not slowing one down, that is slightly irksome but if one is following another car it will slow to keep distance, other wise gently brake and recover the energy to the Battery, something the Kia couldn't do and wasted that energy to heat and wear on the pads/discs.

Regarding the voice guidance all one can do is adjust the voice volume, unless one is blasting out the music one can still hear quite clearly. The guidance is also given in the cluster and HUD.

[Las Palmas]

31 minutes ago, NemesisUK said:

Au contraire, I think they are perfectly suited to hilly. mountainous roads. Battery assistance on the way up and regenerative braking on the way down.

As for the cruise control not slowing one down, that is slightly irksome but if one is following another car it will slow to keep distance, other wise gently brake and recover the energy to the battery, something the Kia couldn't do and wasted that energy to heat and wear on the pads/discs.

Regarding the voice guidance all one can do is adjust the voice volume, unless one is blasting out the music one can still hear quite clearly. The guidance is also given in the cluster and HUD.

When I drive 60 km uphill to get to the fantastic view for neighbouring island, I have engine running all 60 km. When I drive down I have less than 3 minutes till hybrid Battery is full. Also up there is where I can buy extra well tasting small almonds from local, and honey that is far from what is available in supermarkets plus cheese, made like it was very many years ago and tasting incredible.

You call that perfectly suited for the purpose of driving in hilly, mountainous roads.

I do not.

[malcolmw]

We see the "runaway" in our NX under certain conditions. I must admit that I cannot see why the speed is not limited to the set maximum level.

[Lesfac]

I really liked the speed limiting aspect of my Sorento and I'm a bit amazed that the RX doesn't do it. With all the police "safety" camera vans around here it was easy to dial in the speed and relax knowing it wouldn't be exceeded. Now I'll have to watch it downhill.

[ColinBarber]

Standard cruise control on all recent Toyota/Lexus vehicles only controls the throttle to moderate speed, only adaptive CC will use the brakes to keep the correct distance to the vehicle in front - I guess this is to help with emissions/economy by not using the brake.

[Bluemarlin]

20 hours ago, Las Palmas said:

Diesel engines are better reducing speed downhill. A hybrid needs to engage brakes. A CT has a B position in gear selector, that is meant to reduce speed downhill, do not know how RX is taking care of that.

Anyway, hybrid cars are not for mountain areas. On the way up engine is using fuel constant and on the way down hybrid battery is full after a few minutes meaning braking power is wasted turning to heat.

In any vehicle you're using fuel to go uphill. As for driving an RX downhill, as I recall, a couple of winters ago, I was driving in the mountains in Germany and used S mode, which lets you set the highest gear to allow engine braking downhill.

[Rabbers]

21 hours ago, NemesisUK said:

Au contraire, I think they are perfectly suited to hilly. mountainous roads. Battery assistance on the way up and regenerative braking on the way down.

Completely agree.  Also recommend SPORT mode as per Bluemarlin above.

21 hours ago, Las Palmas said:

… Also up there is where I can buy extra well tasting small almonds from local, and honey that is far from what is available in supermarkets plus cheese, made like it was very many years ago and tasting incredible.

I hope you realize, John, that over-stimulation of the gastric juices can result in loss of driver concentration, especially on mountain roads.

[Las Palmas]

8 hours ago, Rabbers said:

I hope you realize, John, that over-stimulation of the gastric juices can result in loss of driver concentration, especially on mountain roads.

Thank you. I did not know it was dangerous to eat goat cheese, almonds and honey.

Not that I am going to stop eating these as always thought natural food was the best.

[welland]

I'm still getting used to my 2012 rx450h after only 6 days of ownership,  and I haven't noticed the downhill runaway while using cruise control yet. But I have noticed something different to my old rx400h:  the rx400h had no engine braking unless the gearlever was in the B position, but the rx450h does have engine braking in the D position. 

[Lesfac]

I have noticed something recently. When I reduce the set cruise control speed while going down hill I can feel active retardation but then it goes away and the car is allowed to overspeed so I have to brake which knocks off cruise control. What an annoying omission by Lexus.

[HotSpur-Lexus]

Not had my Lexus long (less than a week) so new to these 'features'

Wow I didn't know that I was missing out on all this - I never use Cruise Control on my cars - all 4 have their manufacturer's form of adaptive cruise but it never occurs to me to use it 

I was surprised to read above about the nav directions not being accompanied by muted audio - again not tried yet in the Lexus - does it mute when listening to Carplay and using Apple's navigation, as that's what I use in my other cars as its just easy to tell Siri where you want to go and engage...unfortunate that it wont use the headsup display for the nav if not using the cars nav but the phones instead but a small sacrifice to pay as it gives you fixed camera warnings too.

[PeterI]

On my 2020 the audio does mute when the Sat Nav kicks in, the only exception is during a phone call. This works for me when using the car sat nav or android. I do wonder if you're playing audio over Bluetooth? It's possible that the phone is sending music over in phone mode rather than the higher quality audio mode, so the satnav assumes you're making a phone call and doesn't mute.

I tend to use the car sat nav 90% of the time as google maps doesn't drive the HUD it only does the main screen and one behind the steering wheel.