Dead battery

[NewSupraOwner]

Battery in my 2020 Supra won't take a charge, reads 3V. When attempting to jump, I get power to most places. When I hit Start while connected to other vehicle, power flickers intermittently, screen and dash go black, car tries to turn over, barely, but can't. Assuming the battery needs to be replaced. Haven't tried charging it disconnected from car.

Is there anything to be aware of when replacing the battery?

Also, I read that the dealer needs to reset some codes and such -- can I get the details on how to do it myself with the right tools (link to post, if easier)?

Is it possible to provide temp power while swapping? Will providing power while swapping avoid needing to reset codes?

Thanks!

ps: getting the car out of park with a completely dead battery sucks. Lever on the transmission, have to jack it to get at it. What are you supposed to do in an emergency?

Sponsored

 

[MyCorolla]

Also, I read that the dealer needs to reset some codes and such -- can I get the details on how to do it myself with the right tools (link to post, if easier)?

The battery needs to be registered, which you can do with BimmerLink and compatible OBD adapter.

https://bimmerlink.app/

BTW, that also has to be done when battery is discharged and recharged.

 

[NewSupraOwner]

The battery needs to be registered, which you can do with BimmerLink and compatible OBD adapter.

https://bimmerlink.app/

BTW, that also has to be done when battery is discharged and recharged.

Thank you!

 

[GoldenEye]

I just went thru a battery nightmare! My advice, drop it off to the dealership and let them do their thing…

 

[NewSupraOwner]

I just went thru a battery nightmare! My advice, drop it off to the dealership and let them do their thing…

Thanks, but the car won't start, won't take a jump, and is a pain to get out of park to be able to tow it. Kinda stuck.

 

[GoldenEye]

You have to have a powerful jumper box and it will start FROM UNDER THE HOOD CONNECTION! DO NOT TRY TO JUMP IT FROM THE BATTERY!!!!!!!!!!!!!!!!!!! It will drive after you start it, you’ll get flickering dash, every CEL all that shit. Drive it to the dealership and let them do their thing, trust me on this…

 

[Magna Steyr Supra]

Did you pop any fuses?

 

[NewSupraOwner]

You have to have a powerful jumper box and it will start FROM UNDER THE HOOD CONNECTION! DO NOT TRY TO JUMP IT FROM THE BATTERY!!!!!!!!!!!!!!!!!!! It will drive after you start it, you’ll get flickering dash, every CEL all that shit. Drive it to the dealership and let them do their thing, trust me on this…

Thanks. I've got a 5A charger rated for 120Ah (car battery is 105Ah). I only tried to jump it from under the hood, leaving it connected for 30 minutes, revving the connected vehicle to 2k RPM during attempts to start. After having left the charger on it overnight, the voltage hasn't changed.

The car won't turn over and start, so it would need to be towed to then, ultimately, replace the battery. Figure it's easier to replace it myself and then take it in.

What else did the dealer do for you other than swap the battery and reset the codes? If you've got a pic of the work order, that would helpful to see what I'm dealing with.

 

[NewSupraOwner]

Did you pop any fuses?

Not sure yet. Just ordered an OBD adapter (OBDLink MV+) rather than trying to check each one. Do you have an idea of which fuses might blow when shorting out the battery at the starter?

 

[GoldenEye]

@NewSupraOwner a standard battery charger won’t do a thing for that battery, not overnight, not ever! If you can’t start it from UNDER THE HOOD, then you must’ve popped a fuse or something. I had to charge my jumper box 100% before it would start the car from under the hood. I don’t care if you have 15 diesel trucks hooked up to the battery, it will not start!

 

[GoldenEye]

Also, in the future, lock your car every time you shut it off OR push and hold down the radio power button until the computers shut off…

 

[GoldenEye]

You can’t just replace the battery yourself, it needs to be programmed…

 

[NewSupraOwner]

@NewSupraOwner a standard battery charger won’t do a thing for that battery, not overnight, not ever! If you can’t start it from UNDER THE HOOD, then you must’ve popped a fuse or something. I had to charge my jumper box 100% before it would start the car from under the hood. I don’t care if you have 15 diesel trucks hooked up to the battery, it will not start!

Thanks. As mentioned, I only attempted to jump the car from under the hood. Pics are the +/- terminals I used.

 

[GoldenEye]

Make sure your jumper box has at least 14.6 volts. If it doesn’t start, it’ll need to be towed most likely…

 

[NewSupraOwner]

Also, in the future, lock your car every time you shut it off OR push and hold down the radio power button until the computers shut off…

Yup, always do both. I think we had different root causes.

Sponsored