Add Yours: 2023 Toyota bZ4X Owner's Registry

Brake warning light - Call Dealer

1672 Views 9 Replies 6 Participants Last post by Motch6, 5 mo ago

Vern748

Discussion Starter · 5 mo ago

I was doing some work inside the Bz and had the radio going. The system would prompt me a few times every 30+ minutes that the car was going to shut down. I must have let it shutdown a few time and put it into accessory a few times. Maybe 3 hrs of this. Went inside for lunch and then came back out to go somewhere.

I attempted to start it up and, no-go. The dash did a bit of blinking of lights and then got a "Brake waring failure" on the info screen. When I had my Prime, it would do this when the 12v battery was flat, so I understood this behavior. I pulled out my trusty digital Jump Starter, and the Bz turned on. Now the "Brake warning failure" is still lit. Ugh. Going have to take it to the dealer to clear the codes and give me a good bill of health.

Since this is not going to be the first time I do this (hazard of my job), I needed to read into how the Bz charges the 12v battery. The vehicle will charge the 12V system when the traction pack is engaged. So, like vehicles of old, you need to go drive it. The big question here is can I charge the 12v battery using a battery charge ? Do I need to disconnect the battery from the car to charge the battery? Most EVs are always on, so I think that is an important question to answer I charge it that way.

Ugh...stay tuned

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Vern748

Discussion Starter · #2 · 5 mo ago

So, after 20 min of driving around the lights and warnings went away 1 by 1.
The take away, do not run the 12v battery flat.
Have a digital jumper for the 12v battery.

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Reactions: 3

osiris11

· #3 · 5 mo ago

Vern748 said:
So, after 20 min of driving around the lights and warnings went away 1 by 1.
The take away, do not run the 12v battery flat.
Have a digital jumper for the 12v battery.

Thanks for the info

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2wheelsandopenroad

· #4 · 5 mo ago

My right turn signal died today. First year model problems, they happen.

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Reactions: 1

enakffej

· #5 · 5 mo ago (Edited)

Vern748 said:
I was doing some work inside the Bz and had the radio going. The system would prompt me a few times every 30+ minutes that the car was going to shut down. I must have let it shutdown a few time and put it into accessory a few times. Maybe 3 hrs of this. Went inside for lunch and then came back out to go somewhere.

I attempted to start it up and, no-go. The dash did a bit of blinking of lights and then got a "Brake waring failure" on the info screen. When I had my Prime, it would do this when the 12v battery was flat, so I understood this behavior. I pulled out my trusty digital Jump Starter, and the Bz turned on. Now the "Brake warning failure" is still lit. Ugh. Going have to take it to the dealer to clear the codes and give me a good bill of health.

Since this is not going to be the first time I do this (hazard of my job), I needed to read into how the Bz charges the 12v battery. The vehicle will charge the 12V system when the traction pack is engaged. So, like vehicles of old, you need to go drive it. The big question here is can I charge the 12v battery using a battery charge ? Do I need to disconnect the battery from the car to charge the battery? Most EVs are always on, so I think that is an important question to answer I charge it that way.

Ugh...stay tuned

Thanks for educating us on how easy it can be to use up the 12v battery and that it doesn’t charge off the traction battery and what to look for in the process. Do you have the upgraded speakers and amplifier?

I’ve been curious whether the 12v battery is of deep cycle construction since it presumably doesn’t need to generate cranking amps for a starter. If so, then at least it should be able to withstand being rundown all the way better than a typical car battery. Also may be able to replace it with one having a higher capacity if there’s room. Has anyone checked out the stock 12v battery chemistry and specs with that in mind?

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Vern748

Discussion Starter · #6 · 5 mo ago

The battery does charge off the traction motos. Wheels move, battery charges.
It's a standard size but not much capacity. It is likely minimal amps, minimal duty cycles. Just need to power the gauges and the transfer switches to engage the high voltage.

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n6nl

· #7 · 5 mo ago

According to the Getting Started Guide:

12-volt battery (Provides electricity to various vehicle systems such as the SRS airbags, headlights, wipers, etc.)

Basically, everything but the traction motors is 12V powered.

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Reactions: 1

Motch6

· #8 · 5 mo ago

2wheelsandopenroad said:
My right turn signal died today. First year model problems, they happen.

This is crazy weird.... I was dring mine home over the past couple days and all of a sudden my RIGHT signal started blinking fast... remember this from something my dad taught me many, many, years ago... either a Fuse or Light bulb out.... I had stopped to charge anyway, so i got out and played around for a bit and found that the Right Rear light was out!... What the freak! ... brand new! .... ok i know there are some faulty parts sometimes... but serioiusly, now i'm wondering since you had an issue!... Anyway... I was driving over to a dealership to have them look at it, and found out just as I got there, it started working again! DUH!... They said, they could check it but the testing would result in a PASS and they wouldn't know what to look for...

So, i'll be taking it by my local dealership to have them test wiring, and maybe just go ahead and replace the bulb (although, it doesn't explain why its working now).

PS: after playing around with my car today, i had forgotten to pay attention to my power, I ran my 12v down too! Duh... throwing errors that wouldn't go away, even after driving for a bit... So, i used TechStream to clear them all out.

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