My 12V Battery is dying

I wonder if a failing battery can cause the early demise of the capacitor thingy?

 

Update: THANKS Priusasa! Printed out your post and took it to my dealer. The service writer started again with "trickle charger" and "drive it more" but your document shut that down. Got new battery! Cool! NOW, what with these Prius 12v batteries? Is this endemic?

 

Are all these failures on 2023 cars?

 

@priusasa ,

I just looked at that TikTok video for the first time. Interesting to actually see the physical device.

 

How is it working with the new 12V battery and defective sub battery? Just loss of some smart driver assistance features? Are the sub battery and shift messages overwhelming, can't be turned off? Possible to live with, temporarily at least?

 

My car was July 2023 production, from the first Europe customer delivery batch.

I saw on the parts database that there has been one revision to the capacitor module, so maybe the newer version is more reliable. Let's hope... I don't recall when that update occurred.

The messages can be dismissed, but come back again in around 10 seconds, so you are stuck with 2 continuously alternating things on half your dash display, as can be seen in that TikTok video. That seems to be the case for almost all system warnings. Only warning I recall seeing successfully dismissed into the "messages" tab is the "Low fuel" warning.

No actual missing features from the sub-battery system - I think it's just contributing to 12V battery pain, maybe even when it doesn't absolutely refuse a start attempt. Once it's going, it's fine, just the messages. But I guess I'd find myself without brake assist in the event of a 12V failure. (On start failure attempts you can perceive the brake pedal responding weirdly - it's clearly not pressurising properly in advance of the READY. I think the normal startup sequence has the 12V fill the capacitors as you approach or unlock, then the capacitors pressurise the brakes.)

This is happening at the same time as another problem , which is a touch sensor failure on the steering wheel. That lost all the TSS functions wanting hand detection - LKA, LTA, PDA . Also booked in for a steering wheel replacement for that. So that was a total of 3 rotating non-dismissible messages.

Although the sensor and TSS stuff was back working after the 12V battery replacement yesterday - either the battery replacement cleared a code or the dealer did it incidentally while trying to clear the sub-battery code. Wondering if it'll actually come back before it gets the new wheel.

 

Thanks for the response. I just have a little experience with those TSS warning messages when some outside sensor got obscured in a snow storm. I thought it was very annoying, and disabled the assistance features until I got the thing back in the garage. I like that display, and those warnings basically negated it.

I wonder if a failing 12V battery could be a contributor to other failings in components not designed with this in mind.

The car seems to need to have an eye on 12V battery health, generally speaking.

 

Prius C with 9k miles

Yep. I can understand your confusion. do not know where I got the "C" from. Could have been 1 or 2 Prius past. What I do know: 2024 AWD. Sticker says XLE but it has front/rear sunroofs–not standard equipment OR available upgrade (?)

 

44000km = 27500 miles, 2.5 years old.

 

Awesome!

 

I'm going to return a dash cam I ordered. I've had second thoughts about tying into safety sense power, stealthy and plug and play though it may be.




https://a.co/d/02boUezA

 

I hate the idea of screwing something up that would cost thousands to fix. Although....it is easy to uninstall.