1 year old - Got "low 12v battery" warning

Check your battery voltage..after couple hours seating ....without powering on car and do a load test..that will give you health of 12v pack....things you are experiencing are related to weak 12v battery

 

I would say yes. Take to the dealer to check codes, or check them yourself if you can. 12v battery is the weak link in the system IMHO.

 

Definitely take it into get the battery checked. My 1 year old 2016 Prius did the same thing a couple times and ended up having to get jumped. Took it into the dealer and the 12 V battery was dying and they replaced it for free. All fine now.

 

It's interesting that car FINALLY has a specific message about low battery.

The question in your last sentence: of course, why ask, lol. For starters, check the voltage with the car off, with a digital volt meter.

Have you:

1. Left any lights on, doors ajar, etcetera, in past?
2. Been using the car infrequently, left it sitting for days at a time, doing only short trips?
3. Frequently sit listening to the radio in accessory mode?

 

What Mendel asked! ^

 

This just happened to me except attempting to re-start the engine resulted in the same 'dashboard going crazy' thing. I let it sit for 10 mins before trying a third time, and it turned on fine. It has since started fine every time.

I had been listening to music in Accessory mode, while waiting to load onto a car ferry. About 30 mins in I received a phone call and the car relayed it via Bluetooth. Immediately on hanging up the phone, the 12V battery warning flashed up on the dash and all other dash lights flickered, accompanied by several beeps and other warning messages I didn't get chance to read.

I'm very surprised by this, it's not as though I'm a big user of Accessory mode, and my last Prius didn't need a battery change until year 9.

 

How many bars showing on the hybrid battery when you tried to start up compared with number showing when you had earlier switched off?

 

How would this affect the 12 volt auxiliary battery? When the car i switched off, the HV relay is open so the hybrid traction battery is not connected to the car, for safety reasons.

 

It's the HV battery that cranks the engine

 

That would not trigger a "12v low battery" warning, though.

 

You're right, I'll stop digging now.

 

This reads like a cautionary tale for people who like to listen to their radios while parked. Do so in READY mode. You can sit there for days and not run down the 12V battery. The HV battery will keep it charged and the engine will start whenever the HV battery needs a shot in the arm. People camp overnight in these cars with the air conditioner running. I don't even know why it needs an ACC mode.

 

Probably some obscure US law much like the need for Neutral and the inside reverse beeping.

 

I didn't notice a 12volt warning, but 8 mths ago, I had "and all other dash lights flickered, accompanied by several beeps and other warning messages I didn't get chance to read.", though I did see the word MALFUNCTION several times. I was driving at the time, I stopped, POWERED OFF, back on, it started normally, went for 5 months till I took it in for service and asked them to check it - it threw up an error with the BRAKE LIGHT SWITCH. Which is being replaced tomorrow after being sourced from Japan.

 

i'm surprised that the new, larger battery under the hood would drain that quickly. i'd love to know the specs, compared to the old one. this is a disappointment, as toyota made a big deal of how they solved one of the biggest complaints of previous generations.
i'd also like to know if there is a standard size replacement for under $100.

 

I presume the Accessory mode is so you can still use the radio, navigation planner, lights, etc. while in an enclosed space. Using Ready can trigger the petrol engine which wouldn't be ideal. I forgot to mention, when the low battery warning first appeared, after turning the car off, when attempting to start the engine with the combination of brake and the power switch, the brake was very difficult to press, almost as though there was a mechanical obstruction.

I'm booked in at the local dealer on 19/5 for an accessory fitting, and will ask them to take a look at that time.

I have Carista somewhere, maybe I could use that to get at the error codes.

I should add, here in Belgium you're not supposed to leave the engine running while idling, even at traffic lights. Of course most people do, but you sometimes get stuck behind someone who did turn theirs off, only to struggle to get it going again when the lights turn green...

 

what does the o/m say about accessory mode? i think the 12v being dead affects the brake.

 

Voltage is not a proper way to diagnose battery health
It need load test..to see how well it run under load....and also this will give you SOC

Posted via the PriusChat mobile app.

 

The manual says this: