ICE Comes On Upon Gear Shift

[NEPrius1]

I have been the owner of 2010 Prius III since mid-July. So far, it has been a great car. I notice something recently that I do not think existed when I purchased the car in July. When I start the car (having my foot on brake), the ICE comes on as soon as I shift into gear (D or R) then release the brake pedal. It seems odd. I seem to recall that this did not happen until the last few months. It happens whenever I start the car. I know this may sound strange but does the external temperature have something to do with this? I have monitored the battery level and it is always nearly full but the ICE still comes on. I live in northern New England and it seems like this has been more evident since the weather has become colder.

Thanks in advance.

[madelinesonja]

I noticed this too -- I just got mine two weeks ago but it definitely didn't do this for the first week. The ICE comes on as soon as I shift into gear regardless of whether or not I take my foot off the brake. I think it does have to do with temperature / engine warm-up (temps went from low 80s to low 60s over the weekend here--western suburbs of Chicago), so I haven't worried about it, but I would love to hear confirmation that I don't need to worry!

[NEPrius1]

Thanks for the reply. Anyone else see similar conditions?

[a64pilot]

stage 1a? Unless I'm mistaken it has always done it. I believe stage 1a is for engine warm up. Only runs a short time right?

[madelinesonja]

Originally Posted by a64pilot

stage 1a? Unless I'm mistaken it has always done it. I believe stage 1a is for engine warm up. Only runs a short time right?

I waited it out yesterday thinking that it should have only been a minute and wanting to be sure, but it was a little over four minutes before it shut off again. I checked for posts on letting it warm up or not this morning and everybody said to just turn it on and go, so that's what I did today. Mileage was horrible on my drive to work -- barely cracked 40, when yesterday I got 54 -- same conditions, same drive time, so I'm not sure what to make of it.

[yardman 49]

If it's colder outside than the temperature to which you have the climate control set, the ICE will run enough to generate heat for the passenger compartment. It will run long enough to sufficiently warm the engine coolant to accomplish this.

Even though there are some electric heaters to assist with heating the passenger compartment, I believe that the majority of the heat comes from the ICE.

[Bobsprius]

I noticed recently it runs more and it's due to the climate change here in the Northeast.
It will come on without a high heat temp set, and turn off within a minute. But if I put the Heater Temp to 80-HI it will run longer to achieve the temperature. It's totally normal. That's why in the winter months your ICE will run more often. So far I have not experienced any significant impact in mileage.

[spiderman]

Originally Posted by Bobsprius

I noticed recently it runs more and it's due to the climate change here in the Northeast.
It will come on without a high heat temp set, and turn off within a minute. But if I put the Heater Temp to 80-HI it will run longer to achieve the temperature. It's totally normal. That's why in the winter months your ICE will run more often. So far I have not experienced any significant impact in mileage.

+1.

This summer I could get from the garage to the end of the driveway or beyond before the ICE came on. Now as soon as I shift to Reverse/Drive the ICE comes on. I have the climate control set to 66 and the outside air is usually 50 - 55 in the garage. Its got to heat the cab somehow.

[NEPrius1]

Thanks to everyone for the great responses. It appears that the symptom I initially described is related to outside temperature. As I mentioned, I live in northern New England and the symptom has become evident now that the weather has become colder.

[David Beale]

The ICE will start:

1. About 5 -10 sec. after you turn on the car regardless, to warm up the cat. Even if it is already warm and you shut it off for a second and then turned it back on.

2. When the A/C system is calling for heat the ICE will start after about 5 sec. when the coolant drops below about 63 C. The heater fan won't run until the coolant has reached about 53 C.

3. When the traction battery gets lower in charge level (a few bars, but still blue).

4. When you ask for more power than a feather would provide pressing on the accelerator. This also includes when you are in "EV" mode, though the amount of pedal pressure required is a bit greater.

Note that "R" does not use the ICE to power the wheels, except to generate electrical power, but the ICE will probably still run unless you aren't asking for heat or much power, and the cat heating cycle is over.