Domer1982

I've had a 2013 GS450h for a little over a year now. Has anyone noticed that the engine sometimes will still run at idle speed (1000-1100 RPM) even after the car has warmed up and doesn't need it?

In ECO or Normal mode, you may not notice this because you cannot see the tach. But I've noticed that there are many times when there doesn't seem to be any legitimate reason for the engine to be running, but if I switch over to Sport mode I can see that the engine is, in fact, idling. Some examples include coasting to a stop or coasting on a downhill grade on the freeway (accelerator not pressed). The engine is completely warmed up and the battery is at least 75% charged. The dashboard display shows that I'm either running off battery alone or charging the battery with regenerative braking only (i.e., the engine is shown to be OFF), but if I switch over to Sport mode I can see that the engine is idling. And when I come to a complete stop, I can sometimes feel the engine turn off even though the display indicates that it was never supposed to be on at all.

This seems odd to me, as the car could presumably be getting even better mileage if the engine was turned off under these conditions.

Chris8152

You have 2 batteries, the hybrid batteries and the car battery, the car battery is only charged when the engine is running, so if you are using a lot of electrical equipment or like me you only travel short journeys the engine will start to charge it.
I find in sport, sport + mode the engine seems to be running more frequently, I assume this is because in these modes you would need the engine running for a quicker response for acceleration.

Domer1982

Maybe, but this happens often and I don't use a lot of electronics - just the radio. The engine just seems to run a lot more than it needs to.

I agree that the engine runs more often in Sport mode for the reasons you cited, but I rarely use sport mode. I'm talking about times when I'm coasting downhill a slight decline in Eco mode, no pressure on the gas pedal, and when I flip over to Sport mode the engine is idling at 1100 RPM. It didn't start up when I switched over - I would have seen and felt that - it is already running. And when I come to a stop, I can feel the engine shut off after 5-10 seconds even though the display says it was never running at all.

Chris8152

Not sure about that one, I did try to replicate your situation but I found the rev counter showing zero, the engine was not running, I don’t know what types of journeys you do, try giving the car a good 10 mile run at speed and then see if it does the same thing.
I thought I had problems with my MK3 450h a couple of years ago, the engine would not stop running for 2 days, even when stationary, I was told because of my usage the main car battery was not getting a good full charge, so I gave it a good run and that seemed to solve the problem.

1fuzzybk

Old topic, I have the Heads Up Display, it's useful for displaying the tach even when in Eco mode. With this, I have noticed the engine will always run if your going faster then 43mph. Even if your going down a hill with your breaks on. The EV indicator is a good measure if your engine is running or not. It will not light up if the engine is spinning at all.

As for the engine running when it could be shut off (at lower speeds). It seems hard to identify what it takes to shut down and run on electric. little to no throttle and lower speeds are better. Going along the same route is it is easy to guess when it will go EV as its repeating. The problem is guess when it will go back to EV after the engine has started to run. I think it also involves the emissions system (if the car has been off for a while) as it has to warm it back up.