Engine kept running during idle with no battery charging

This happened few times already and I don't think it is normal behavior of a prius.

Symptoms:
Engine keep running during complete stop or parked(lasted about 2 min or more when I tested it)
Does not charge the battery according to the monitor or do anything
Happens at night time(cold temp) and daytime(hot temp), A/C off, heaters off
Usually happens after a long high way/fast speed drive
The problem goes away after turning on and off

History:
Recently swapped the ICE engine due to head gasket bolt issue. (could it be some wires were mis-plugged?)
Only added injen intake for performance

Video:

Can anyone tell me what the issue is? Thanks.

 

how many miles on the hybrid battery?

~148k

how is the 12v health?

just tested the battery and it was 12.6v

any dash lights?

no dash light, everything seems normal.


is the battery cooling fan running?

Will clean that today according to remedied posted on here


you might need tech stream to see what's happening

Will get one on ebay if the problem keep persisting.

This happens in drive mode with braking or parked mode. I didn't not test it in neutral.


Is it REALLY HOT where you are ?

It's getting hot over here in Socal but it also happened at night(~65-70F)


Was the A/C running at the time ??

I turned off A/C, heater, and radio


First thing you should check is the coolant level (s) and the radiator fans.

The engine temp might be creeping up a bit and it is running to circulate the water.

Coolant level is fine, radiator fan is not on.


Also check the radiator to be sure there isn't a plastic "WalMart bag" stuck in it.

nothing under the car





I just cleaned out the battery vent today, didn't touch it for 5 years. Will report back to see if it helped or not.

I noticed while my engine kept running during idle, my gas mileage went down little a bit.

 

Yea my bad, I meant nothing under the car near the radiator fan or behind the grill.

Update:

So far so good with the battery cooling vent cleaned. My mpg actually went up a little, not sure how that little vent can really mess with the engine. So remember guys, always clean your vent. #ventsmatter

Will update again if the problem still persist. Thank you to all who replied.

 

I'm guessing the traction battery was at a point where they don't trigger the overheating sensor since the fan was not broken.

So far my mpg actually went up ~5mpg, no issue of engine running continuously. I'm also going to add this to my cleaning routine and I encourage everyone to do so as well.