problem to start the prius 2016 after almost 4 month not driving

At this point the damage is done. The car should be driven once a month and not sit that long. It's bad for both the batteries. This is in the manual and I believe it's posted somewhere under the hood or something as well, at least it was on the Camry hybrid if I remember correctly. You may have damaged the hybrid battery as well. Cant tell without further investigation and a scan tool and probably the Dr Prius app.

 

Just replace the 12v battery when you get back.

 

She probably didn’t press the POWER button again to shutdown the car. Without pressing the brake pedal, press the POWER button and it should shutdown and stop making any sounds.

You may not be able to “jump” start the car with a dead battery. It could be too far gone to accept a jump. You might have to remove it and carry it to “AutoZone” for a check. If you end up needing a replacement, I would recommend the EverStart MAXX H4 from Walmart for $160. It’s an exact fit and comes with 3-year warranty. I just replaced my original from 2016 with this battery last week.

 

EverStart Maxx Lead Acid Automotive Battery, Group Size H4 12 Volt, 480 CCA - Walmart.com

 

6 month hiatus with a connected battery is guaranteed to kill it. For next time, charge before leaving and then disconnect neg cable. Or just remove the battery and store indoors.

Something not adding up here. Maybe have AAA or similar come by, check that it can’t shut down, disconnect aforementioned neg cable.

Is the car in a secure garage?

 

Yes, it sounds like a very low or dead 12VDC battery. The buzzing sound is usually a partially closed relay and/or voltage leakage to some alarm/warning speaker.
When you replace the battery, it's due, you may get some error codes. That's normal, clear the codes and see if they reappear after driving a few days. The CPUs was starved for power and wasn't thinking correctly - ergo error codes.
Next time you go on a long trip, place the battery on an automatic battery tender. This will avoid your neighbor from having to turn the car on. I believe your supposed to leave the car in 'ready' mode for at least an hour every two weeks - in a well ventilated area, in case the engine needs to start to keep the batteries up. Check user's manual, under long term storage. The car can take care of itself, but turning it on for 10 minutes isn't going to overcome the battery losses incurred for the number of CPUs that needs to boot-up. This simply isn't enough time for the system to recharge the batteries.

Hopes this helps...

 

For the hybrid battery I think it’s 3 months.

 

Battery tender does nothing for the hybrid battery pack. The car needs to be turned on and driven once a month.

 

FWIW from section 1.4 of the seldom read Owners Manual:
Charging the hybrid battery (traction battery)
As the gasoline engine charges the hybrid battery (traction battery), the bat- tery does not need to be charged from an outside source. However, if the vehicle is left parked for a long time the hybrid battery (traction battery) will slowly discharge. For this reason, be sure to drive the vehicle at least once every few months for at least 30 minutes or 10 miles (16 km). If the hybrid battery (traction battery) becomes fully discharged and you are unable to start the hybrid system, contact your Toyota dealer.

 

The amount of time will vary with the battery chemistry. NiMH self discharges faster than Li-ion.

 

True, but the OP has a Gen 4, two wheel drive so the NiMH doesn’t apply. FWTW

 

IIRC base model gen 4 (level 2?), non AWD, had NiMH.

 

If your not using a battery tender, in my experience, an old battery in a modern car will usually be down around 12 VDC in 2-3 weeks, when parked. The older the battery the shorter the time frame. That's why I stated, get the car into ready mode for an hour - every two weeks. Margin of safety. Also make sure there's no flammables near or around your CAT or exhaust system. Make sure you have at least a half tank of gasoline.
If your using a battery tender, depending on battery chemistry, you can probably get away with not turning-on the car for at least 3 months. You will have to get the car into ready mode for at least an hour to let everything get charged up to a point, so you can shut-down for another 3-4 months.

Hope this helps...

 

Unfortunately none of that charges the hybrid battery pack which is way more expensive than the accessories battery. These cars need to be driven periodically once a month just the way it is.

 

You may be right, and it’s always good to err on side of caution. Still, IIRC, for hybrid battery I think Owners Manual recommends at least every 3 months.

 

You can try charging the battery first before replacing

 

Some FWD trims used NiMH. Toyota actually switched to Li-ion for half a year of Rav4 production when NiMH supplies were low.

Putting the hybrid into ready mode will start the car. The hybrid will start the engine, and the warm up cycle will put charge into the traction battery. If the SOC is still at minimum, it will run the engine until it is charged. An hour on for the 12V is plenty for the traction battery to charge up

 

Let me rephrase, none of that properly charges the traction battery. It's bad for lion batteries to maintain charge above 80% or below 20% for extended periods of time. The battery needs to be discharged and charged. There's a reason why the manual says drive it not put a battery tender on it and put it in ready mode.

 

My 2018 Two has NiMH.

 

My 2018 Two has NiMH.