Hi,

I'm a new owner of a `10 RX450h, it is a great car, much was learned from this forum!

We have a Prius 3rd gen as well for a few years now, so I'm familiar how the hybrid system works.

My "problem", in the RX when in very slow stop and go traffic, the engine kicks in even at the lightest accelerator pedal movement, the Energy meter is at the very start of the "electric section". Otherwise the "electric section" works great, after engine acceleration I release the pedal so the Energy meter will be in the "electric area", then it runs on electric only, and kicks in only after leaving the "electric section". Only problem is when starting from a standstill or from "creeping". The engine is warm, the battery is full.

I thought this should work like this on the RX, but a few times, in some conditions, I can start and drive off from standstill with electric mode only, but this is very rare, and I don't know what is different in these cases.

How does your RX450h work?

Many thanks in advance.

 

My RX has a mind of its own. Sometimes mine will behave just like yours and other times it'll stay in electric as much as possible. In the end, this is 'normal' for the RX. We only perceive it as a problem since we're used to the Prius.

 

It's pretty cold here now, I had a longer drive today so the coolant warmed up right to the middle level, and after that I could start off in electric just as with the Prius. I think this must be related how the engine/coolant is warmed up correctly.

Many thanks for the reply.

Now just to solve the rear seats rattle...

 

Welcome to CL, Wallander. Do you have the 450h in eco mode? I find the gas engine turns on less when it's on and cold out but at the cost of heating up slower during short trips. It's better the further you go.

 

Thanks, Anita, I've tried ECO mode, also turned off AC, but that did not seem to make a difference.

So just another reason for Spring to arrive

 

In my '13 RXh - when the battery is moderately-to-mostly charged - and if I keep the meter in the solid-colored ECO mode - I can get to approximately 42 MPH until the engine starts.

Things that will cause the engine to start earlier:

Battery needs charging
Heater needs the engine to start to provide heat to occupants (turn off heater/AC to eliminate)

Note that at speeds over approximately 40~42 MPH - and unless going downhill or when not needing forwarded thrust - the engine will run - for a couple of key reasons:

The electric motor speed is too fast and the ICE needs to run in order to slow down the motor.
The ICE is always spinning (not necessarily "running") at vehicle speeds over 40~42 MPH.

Now that I'm here in Florida for the winter, my car loves the flat ground and warm ambient temperatures - and the traffic is not at the Michigan pace with respect to race car launches from traffic lights - so I can actually start and cruise up to 35+ MPH (I don't try to reach 40 MPH, as I would then risk too many one-finger-salutes from the parade behind me were I to do it) on battery only.

 

For the rear seats, are they fully pushed back and "locked" into place? I had gone months before I realized I didn't put the seats all the way back into their upright and locked position after I had lowered them for hauling stuff. Just a thought.

 

If the air temperature is cold, it really doesn't matter if the engine is warm or not, the engine will start when applying the gas from stop, even just removing your foot from the brake pedal will cause the engine to start. I notice this quite often waiting in the drive-thru coffee shop. This is a result more of predictive process:

a) The vehicle is stopped, but now the driver has removed foot from brake
b) It's cold outside
c) Even with a warm engine, driving without the engine will cause it to cool down rapidly

Result: start engine immediately, keep it warm instead of risking letting it cool down.

 

I can attest to this. I drove 4 hours straight yesterday (highway mileage) and after my exit, I turned off my RX. I turned it back on within 2 seconds for the heck of it and the engine immediately fired up. The ambient temperature was in the low 50s. I just find it weird how Toyota programmed the RX to respond differently than the Prius/CT where as those cars seems to want to be in electric motor as much as possible.

 

I would think it's to remove the sensation of serious sluggishness which is the main problem with the Prius and CT from a standstill

 

Sluggishness ?

Prii (is that the plural of Prius?) are usually the first away from the light around here. Perhaps the drivers have "something to prove" - but, they scoot pretty well.

They're certainly NOT holding up traffic.

 

The start-up after the car has been turned off, even if it's warm, is due to the fact that the engine computer doesn't know how long it was off. The engine start is to get the oil circulated and the engine primed for quick response should you step hard on the gas pedal. You wouldn't want the engine to jump to high RPM with no oil lubricating the internal parts. Once the initial engine run after startup the engine usually shuts down, if it is already warm. I will agree with you, it would be nice if there was a super economy mode, that would use only electric as much as possible, even if it meant running down the traction battery to a lower level, or slowing down the ICE response. I'm annoyed by the engine running more in cold weather just because the air is cold, even after the engine is hot.