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Discussion Starter · #1 ·
I was driving into work this morning in heavy traffic and I noticed that my ICE was running the entire time and Even at a complete stop it was running. Here is what I observed:

1. I was traveling under 40mph
2. I was going down hill
3. The AC was off
4. The battery was 75% charged

I also noticed that when I cut off the fan the engine cut off so it seemed that the can was acting like the AC was on when it wasn't is this normal?
 

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How long were you driving before the ICE finally cut out? It will tend to stay on during the warmup period. Also be sure you weren't accidently in B mode, as that tends to keep ICE running.
 

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I don't know about where you are in Georgia, , but it's been really cold here in SW Missouri, the ICE runs quite a bit more in cold weather.
 

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Discussion Starter · #4 ·
I had beed driving for about 45 mins before I noticed the problem and the outside temp was about 75 degrees.
 

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The Energy Monitor does not tell you all that the engine is doing.

1. Engine is running to propel the car - on Energy Monitor.
2. Engine is running to recharge the battery - on the Energy Monitor. (BTW: Classic Prius usually hangs out at the 75% charge level all the time, occasionally the 50% point, and only the full or 1/4 in large hilly areas (or 1/4 if stuck in traffic idling long enough).
3. Engine is running to warm itself up for emissions reasons. If the blue cold coolant light is on, your engine is probably running. About the first 5 minutes of a trip, maybe up to 20min if it is really cold outside and the car has been sitting outside overnight. will not show up on Energy Monitor.
4. Engine is running to provide "waste" heat for the passenger compartment - will not show up on Energy Monitor
5. Engine is running to help calibrate charge levels in the hybrid battery. (This is seen in Classic Prius when the engine suddenly starts up when you put the car into Park...) It may or may not show up on the Energy Monitor...
6. Engine is running to power the AC compressor via belt on the Classic Prius. If you have the left fan position dial on the windshield for front windshield defrosting, that will use the AC for dehumidifying. Windshild/floor is less agressive in the AC compressor use. You can also get the engine to run almost constantly if you use the MAX button for the AC, whereas the engine/compressor will just cycle as needed if you only used the regular AC button. Running the AC compressor will not show up on the Energy Monitor.

So, how cold was it this morning? How long was your drive before you noticed the engine on at stoplights? What were your climate control settings?
 

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Ah, failed to notice 2001. Don't know the logic the classic uses ICE with climate control, though I understood ICE is forced on only when the compressor is actually needed. Sometimes though, ICE will stay on longer than one would expect, probably to keep the catalytic and O2 sensor hot.
 

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Discussion Starter · #7 ·
OK I figured it out I had the vent set to defrost and apparently that uses the AC compressor reguardless of whether the AC button is on or not.

atleast nothing is wrong :)

Thanks for your input!
 

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Yup, that would do it. It should stop though when the compressor cycles off, as I am sure it does not run constantly even in defrost, only enough to keep the evaporator cold for dehumidification.
 

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iggy1iggy said:
OK I figured it out I had the vent set to defrost and apparently that uses the AC compressor reguardless of whether the AC button is on or not.

atleast nothing is wrong :)

Thanks for your input!

Yeah, on some nights leaving work (lots of traffic lights leaving from work) I'll just use floor/windshield when sitting at the light, and then switch to full windshield whenever moving or if the engine came on anyways. (I've got a CoastalETech engine run indicator.) It's really eerie sitting at a traffic light with the engine on, turn the dial off of windshield, engine turns off, turn dial back to windshield and engine comes back on...

Most cars do use the AC compressor for dehumidifying when on the front windshield defroster setting. Unfortunately, the Prius is not one of those cars that also turn on the AC light when using the AC condensor with the defrosting action...
 
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