Energy Monitor question

[jyoungprius]

Why is it that most of the time when I come to a stop at a traffic light the engine shuts off and the Energy Monitor shows no flow of energy from the engine.... but at other times after stopping at a traffic light, the Energy Monitor shows the same lack of energy flow from the engine, yet I can feel and hear the engine still running. If the engine is still running when at a traffic light where is that energy flowing to? In other words, shouldn't I be seeing arrows flowing out of the engine icon when the engine is clearly running?

[Frank Hudon]

some times when the ICE is in the warm up stage and to l lesser extent when the temps of the O2 sensors are low Ie: low mv. output, the ICE will still run but no energy is sent to the battery if the car is at a stop. This also happens if the car has just come to a stop and the above parameters are not met, then after 20-30 seconds it goes into stealth. The ICE was probably at the 70C temp threshold or very close. Pretty well nomal Prius operation.

[Brian K]

The ICE will also come on when cabin heat is called for even though it isn't being used for propulsion. I know it's spooky to hear it running without arrows showing where the energy is going. On a cold day with climate control set to room temperature and no sun shining inside, start it up in "park" and just sit tight to experience this.

Relax, just let the computers do what is needed. Your Prius is normal.