I want to alert everyone of an issue with the auxiliary 12 volts battery in the new Prius prime 2024

No, they only use the GR8 diagnostic/charger. Researching the GR8, apparently most dealerships use this because it provides a receipt-like “ticket” that allows them to submit a warranty claim.

According to the owner’s manual, there is a criteria related to the “20 hour rate capacity”; if it is low, “even if the time period where the vehicle is not used is a short time, the 12-volt battery may discharge and the hybrid system may not be able to start.”

In my case, I drove the car on Sunday afternoon and it failed to start on Wednesday morning.

Reading about this problem here and elsewhere, why aren’t owners making a big protest back to Toyota? I’m planning to contact Toyota, Consumer’s Report, and Motor Trend. Motor Trend should be made aware of this issue with their 2024 Car of the Year!

 

Just found this in the owner’s manual. After I last drove the car, it was put on the charger when we got home and I left it overnight since it wasn’t going to be completely charged until 11:30 PM. Removed the charging system at ~8:30 AM the next morning and didn’t try driving it until two days later.

 

if you don't drive too often you might need a maintainer

 

The dealer texted me this afternoon that they tried to start the car and it didn’t work, a day after they said everything had checked out ok. Very glad that I didn’t listen to them to pick it up yesterday!

I asked them to see if a larger capacity battery, such as the Truestart 470CCA mentioned by another poster, could be installed. I also bought the NOCO GB40 battery booster in case this happens again…

 

I believe the 12 volt is an AGM battery.

 

Somebody's gotta do a phantom load test. It's not hard; might get to the bottom of this. It could be excessive phantom load, or the hybrid battery charging causing excessive draw, or a combo of the two.

 

Ok so the battery issue just reared its ugly head. Have a 2023 for about 1 year, battery dead this week. Toyota roadside boosted it, dead again 3 days later. Replaced battery by Toyota (supposedly bad battery as it failed the tests)

I’m fairly sure I did everything correctly with the battery as per best practices and it still died.

 

does canada have the software tsb? don't count on the dealer to know.

 

Did you check to see if you have a tracker tied into your OBD port under the dash?

 

Not on the '23-24 Prius models.

Conventional flooded lead acid 12v battery.