Fault Code [Aged Auxilarry Battery] after Main and Aux Battery Replacement

winston8484 · 02-11-2025, 03:02 AM

G30 530E 2018

Good day all : ), today i attempt to replace both my main and auxilarry battery.

I replaced both the 90AH AGM main battery and 60AH AGM battery, perform a battery registration and clear all fault code with my Ancel BD300.

I realise after about an hour of drive, when I rescan my car, a fault code [ 218219 ECM Engine Control Module : Starter Unit Charging Controller for auxiliary batteryL Aged auxiliary battery] show in the app.

Would appreciate help on what could explained this?

Alpine530e · 02-11-2025, 10:45 AM

Did your scan tool have an option to register the main and aux battery separately? If not you only registered the main battery. I don't know if your scan tool will allow you to register the aux.

ISTA has an option to register the aux battery for the 530e. It's an ABL under Vehicle management>service functions>body>voltage supply>hybrid car>starter unit>auxiliary battery: register battery replacement.

capese21 · 02-13-2025, 03:22 PM

I don't believe the aux battery needs to be registered and even if it did you've replaced like for like.

The 530e maintains both 12v batteries from the HV system.

I would drive the car for a few days then clear the codes and re scan.

I've had the aged aux battery showing as a fault code for over a year and there are no issues. It will illuminate a CEL when the fault needs attention.

RichieF5 · 02-14-2025, 12:44 PM

Yes it does need to be registered. I done it on my 530e.

CnSky · 02-14-2025, 02:02 PM

The SOS battery throws a very similar fault and most BMW techs can’t differentiate because they don’t check the code. You sure it’s not that battery in the headliner below the shark fin that’s continuing to give an error. Eventually it gives an error in the binicle but prior to that ISTA will show you a fault months in advance of the error that shows up in the car.

Edwinvb · 03-21-2025, 02:09 PM

winston8484 I have the same fault code after replacing and registering the auxiliary battery. In my case I did a ista scan after I’ve noticed that the heater didn’t work on hybride or electric drive. Ista only displays aged auxiliary battery. So I’ve replaced that one. Still no heat and the error code remains. Did multiple delete attempts without any luck. Did you get it fixed?

02-11-2025, 03:02 AM	#1
winston8484 Registered 0 Rep 1 Posts Drives: BMW G30 530E Join Date: Feb 2025 Location: Malaysia iTrader: (0)	Fault Code [Aged Auxilarry Battery] after Main and Aux Battery Replacement G30 530E 2018 Good day all : ), today i attempt to replace both my main and auxilarry battery. I replaced both the 90AH AGM main battery and 60AH AGM battery, perform a battery registration and clear all fault code with my Ancel BD300. I realise after about an hour of drive, when I rescan my car, a fault code [ 218219 ECM Engine Control Module : Starter Unit Charging Controller for auxiliary batteryL Aged auxiliary battery] show in the app. Would appreciate help on what could explained this? Attached Images
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02-11-2025, 10:45 AM	#2
Alpine530e New Member 8 Rep 9 Posts Drives: BMW 530e Join Date: Oct 2020 Location: NA iTrader: (0)	Did your scan tool have an option to register the main and aux battery separately? If not you only registered the main battery. I don't know if your scan tool will allow you to register the aux. ISTA has an option to register the aux battery for the 530e. It's an ABL under Vehicle management>service functions>body>voltage supply>hybrid car>starter unit>auxiliary battery: register battery replacement.
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02-13-2025, 03:22 PM	#3
capese21 Private First Class 43 Rep 126 Posts Drives: 5 series Msport G30 530e Join Date: Mar 2023 Location: Warwickshire UK iTrader: (0)	I don't believe the aux battery needs to be registered and even if it did you've replaced like for like. The 530e maintains both 12v batteries from the HV system. I would drive the car for a few days then clear the codes and re scan. I've had the aged aux battery showing as a fault code for over a year and there are no issues. It will illuminate a CEL when the fault needs attention.
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02-14-2025, 12:44 PM	#4
RichieF5 New Member 14 Rep 16 Posts Drives: F10 520d 2014 Join Date: Aug 2021 Location: Ireland iTrader: (0)	Yes it does need to be registered. I done it on my 530e.
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02-14-2025, 02:02 PM	#5
CnSky Major 414 Rep 1,073 Posts Drives: BMW 530E 2017 Join Date: Aug 2013 Location: Ireland iTrader: (0)	The SOS battery throws a very similar fault and most BMW techs can’t differentiate because they don’t check the code. You sure it’s not that battery in the headliner below the shark fin that’s continuing to give an error. Eventually it gives an error in the binicle but prior to that ISTA will show you a fault months in advance of the error that shows up in the car.
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03-21-2025, 02:09 PM	#6
Edwinvb Registered 0 Rep 1 Posts Drives: BMW 530E Xdrive Touring lci Join Date: Mar 2025 Location: Netherlands iTrader: (0)	winston8484 I have the same fault code after replacing and registering the auxiliary battery. In my case I did a ista scan after I’ve noticed that the heater didn’t work on hybride or electric drive. Ista only displays aged auxiliary battery. So I’ve replaced that one. Still no heat and the error code remains. Did multiple delete attempts without any luck. Did you get it fixed?
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