2001 Prius - Stealth Mode

[MaxFrenzy]

Hi, I am new owner of a 2001 Prius. I was hoping you all could give me a hand trying to understand something here. Through some research online and through this board, I tried to educated myself on the functioning of the Prius. It is my understanding that the Prius is capable of driving in battery only (stealth mode) under certain circumstances

Those being:
1. The engine is sufficiently warmed up
2. The batteries have sufficient power
3. You are traveling at 42mph or below
4. You are not attempting to accelerate quickly.

I am certain over the weekend that I met that criteria several times, one specifically being when I was stop and go in Chicago traffic for an hour. Throughout that entire time, the lcd display always showed there was engine assistance. The only time the engine shuts off is when I come to a complete stop, but promptly turns back on when I start moving.

Am I understanding the technology incorrectly? Does this not happen in a 2001 prius (U.S.A. model)?

Thanks for the help!

[john1701a]

One of the improvements that came with the newer HSD version was the upgrade to electric A/C. Before that, the engine would have to run to keep you cool.

Another was the tolerances for when the engine shut off and came back on. This was quite obvious with temperatures below 20F. It happens at the other extreme some too, as you likely just saw in the summer crawl through heavy traffic... even without the A/C running.

Figure if the wait will be longer than 15 minutes, the engine will eventually run briefly for some reason or other.

.

[MaxFrenzy]

Originally Posted by john1701a

One of the improvements that came with the newer HSD version was the upgrade to electric A/C. Before that, the engine would have to run to keep you cool.

Another was the tolerances for when the engine shut off and came back on. This was quite obvious with temperatures below 20F. It happens at the other extreme some too, as you likely just saw in the summer crawl through heavy traffic... even without the A/C running.

Figure if the wait will be longer than 15 minutes, the engine will eventually run briefly for some reason or other.

.

The AC issue you've mentioned definitely could be the culprit here. It's been pretty hot in Chicago and I've been running it when driving. I suppose a good test would be to give it a try around the neighborhood with just the windows down and see if I can ever get the car to get to a state where the engine is cut off and I'm riding around on battery only.