Got the key battery warning light !

lordbmw · 12-14-2019, 07:04 PM

Happened yesterday.

Looks like I'll have to get out my soldering iron from what I've read online

Has anyone else had this happen?

eugenecp · 12-14-2019, 07:41 PM

Do you have CAS? The battery replacement is easy.

lordbmw · 12-14-2019, 09:34 PM

Quote:

Originally Posted by eugenecp

Do you have CAS?

No.

clegg · 12-14-2019, 09:40 PM

If you can start your car without putting the key in the dash as mentioned, the fob has a 2032 lithium battery.

lordbmw · 12-14-2019, 09:58 PM

Quote:

Originally Posted by clegg

If you can start your car without putting the key in the dash as mentioned, the fob has a 2032 lithium battery.

Car will not start without inserting the fob.

Monster900 · 12-14-2019, 10:12 PM

Quote:

Originally Posted by lordbmw

Happened yesterday.

Looks like I'll have to get out my soldering iron from what I've read online

Has anyone else had this happen?

Your key fob battery needs charging. Keep driving the car and it will charge eventually. It happened to me once when valet the car.

Serf27 · 12-15-2019, 01:25 AM

I let the car idle for 20 mins the other day and it charged it, but you could also just drive it as stated above.

lordbmw · 12-15-2019, 11:11 AM

Quote:

Originally Posted by Serf27

I let the car idle for 20 mins the other day and it charged it, but you could also just drive it as stated above.

I daily drive the car.

I think the battery is most likely failing to hard charge.

It's like your phone, you'll need to replace the battery (or the phone) eventually.

ctuna · 12-15-2019, 06:28 PM

keyfob repair
https://www.e90post.com/forums/showthread.php?t=1510527
keyfob guy
https://www.bimmerfest.com/forums/sh...d.php?t=903551
https://www.bimmerfest.com/forums/sh...d.php?t=874226
https://www.facebook.com/GcodingBMW
https://www.e90post.com/forums/showt...&highlight=key
https://www.e90post.com/forums/showt...ht=key+charger

John 070 · 12-16-2019, 11:52 AM

This story reminds me of when my 335 was brand new and it stalled. The SA told me your issue is you never put your fob into the dash and the battery is dead. I said yeah but my fob has a 2032 inside. He said you keep going to the internet, you're going to get bad information (this is back in the day when on this very forum we tried to keep track of the latest greatest software updates and the SA told me stop going to the internet it's bad).

oVeRdOsE. · 12-16-2019, 11:59 AM

do we need recoding after battery swap?

if yes,
can't we do just like old school gameboy/n64 cartridge ?

-Solder a new battery in parallel on fob contact,
-then remove the old battery,
-insert a new one,
-de-solder parallel backup battery.
?

12-14-2019, 07:04 PM	#1
lordbmw Captain 270 Rep 790 Posts Drives: 2010 BMW 335xi Coupe (AT) Join Date: Sep 2016 Location: Alexandria, VA iTrader: (0)	Got the key battery warning light ! Happened yesterday. Looks like I'll have to get out my soldering iron from what I've read online Has anyone else had this happen? Attached Images
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12-14-2019, 07:41 PM	#2
eugenecp Private 19 Rep 77 Posts Drives: 2009 BMW 328i Convertible Join Date: Aug 2019 Location: TX iTrader: (0) Garage List 2007 Toyota Sienna [0.00] 2004 VW Touareg V8 [0.00]	Do you have CAS? The battery replacement is easy.
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12-14-2019, 09:40 PM	#4
clegg First Lieutenant 87 Rep 301 Posts Drives: 335i E92, 435i F32,X5 F15 Join Date: Apr 2019 Location: O'Fallon, MO iTrader: (0)	If you can start your car without putting the key in the dash as mentioned, the fob has a 2032 lithium battery.
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12-15-2019, 01:25 AM	#7
Serf27 Brigadier General 2851 Rep 4,322 Posts Drives: 335i Join Date: Apr 2018 Location: Sitting in a BMW. iTrader: (-1)	I let the car idle for 20 mins the other day and it charged it, but you could also just drive it as stated above.
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12-15-2019, 06:28 PM	#9
ctuna Lieutenant General 1911 Rep 13,103 Posts Drives: 325xi 06 wagon MT Join Date: Jan 2010 Location: Santa Cruz, Ca iTrader: (0)	keyfob repair https://www.e90post.com/forums/showthread.php?t=1510527 keyfob guy https://www.bimmerfest.com/forums/sh...d.php?t=903551 https://www.bimmerfest.com/forums/sh...d.php?t=874226 https://www.facebook.com/GcodingBMW https://www.e90post.com/forums/showt...&highlight=key https://www.e90post.com/forums/showt...ht=key+charger
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12-16-2019, 11:52 AM	#10
John 070 Lieutenant General 1705 Rep 14,829 Posts Drives: 335i cpe Join Date: Oct 2006 Location: ZSP/ZPP/ZCW iTrader: (0)	This story reminds me of when my 335 was brand new and it stalled. The SA told me your issue is you never put your fob into the dash and the battery is dead. I said yeah but my fob has a 2032 inside. He said you keep going to the internet, you're going to get bad information (this is back in the day when on this very forum we tried to keep track of the latest greatest software updates and the SA told me stop going to the internet it's bad).
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12-16-2019, 11:59 AM	#11
oVeRdOsE. Lieutenant Colonel 2706 Rep 1,537 Posts Drives: F25 E91 Audi Avnt E90 Cayenne Join Date: May 2018 Location: mtl iTrader: (0)	do we need recoding after battery swap? if yes, can't we do just like old school gameboy/n64 cartridge ? -Solder a new battery in parallel on fob contact, -then remove the old battery, -insert a new one, -de-solder parallel backup battery. ?
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