Need Help!! 2012 Ml350 W166 battery issue.
#1
Junior Member
Thread Starter
Need Help!! 2012 Ml350 W166 battery issue.
i need help. My main battery signal (red) on dash board came on yesterday.
I barely made it home. I purchase a new battery of the same specs from autozone to replace it. My car turns on but the red warning sign does not go away.
Is my alternator bad or
Do i need to reset the ecu. How do I do that.
I also don't know if I need to replace the aux battery I'm not sure where is it. Or if I need radio codes I need instructions. Need help.
Would like to do it myself and avoid going to a shop.
Thanks.
I barely made it home. I purchase a new battery of the same specs from autozone to replace it. My car turns on but the red warning sign does not go away.
Is my alternator bad or
Do i need to reset the ecu. How do I do that.
I also don't know if I need to replace the aux battery I'm not sure where is it. Or if I need radio codes I need instructions. Need help.
Would like to do it myself and avoid going to a shop.
Thanks.
#3
Junior Member
Thread Starter
I have a newer model and I can't find the aux battery. I had seen same vid and did as is. But since I can't find my aux battery to check it. I don't know we're my issue is at . Thanks for the info
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Mercapotamus (02-21-2017)
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#8
MBWorld Fanatic!
Originally Posted by Jose3147
The main is easy. Just like the Vid you posted. For the main You need a H8 AGM battery. You can get it at any auto parts.
https://www.batteriesplus.com/batter...iesel/sli49agm
How long did it take you?
#11
#12
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Originally Posted by Mercapotamus
Fyi - I got the same battery from Sam's Club for $170 last month. Works fine so far.
#14
#17
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Originally Posted by burnout
What' the warranty on the duracell?
48 Month Free Replacement Warranty
2x more cycle life than conventional batteries
20X more vibration resistant than conventional batteries
100% spill-proof and maintenance free AGM technology
2014 Mercedes Benz ML350 V6 3.0L 850CCA Diesel Car and Truck platinum AGM battery
#18
Junior Member
Why is that battery so much smaller than the auxiliary battery that the car came with? This diagram shows our cars have the main battery (1), auxiliary (2), and a back up (3) battery. That small one in your pic looks to be the back up battery. I have a W166 and trying to replace my auxiliary battery replaced, but I'm a little confused.
(3)
#19
That is a darn good question. Why is that auxiliary battery so small or why is the bracket so big? That looks like what must be the hold down bracket on the left side of the photo. In the 2013 ML350, is there an auxiliary battery located in the back, right side, behind the panel? Can anybody explain what this extra battery does and what symptoms occur when it goes bad? Is there a specific procedure to follow to replace it?
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zatsme7 (12-29-2021)
#20
Why is that battery so much smaller than the auxiliary battery that the car came with? This diagram shows our cars have the main battery (1), auxiliary (2), and a back up (3) battery. That small one in your pic looks to be the back up battery. I have a W166 and trying to replace my auxiliary battery replaced, but I'm a little confused.
(3)
#21
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2008 E350 (W211 @170K), 2012 ML350 (W166 @119K), 2014 E350 (W212 @100K), 2015 ML350 (W166 @96K)
From the diagram, it seems the W166 platform can come with ECO/Start/Stop or not. Those with ECO/Start/Stop require a larger auxiliary battery (see 2 in the diagram), while those w/o ECO use the smaller battery (see 3 in the diagram).
The small battery ( 3 ) works as a backup for the shift selector and other minor electronic components in the vehicle, while the larger one helps to run more features when the car is temporarily OFF: brake HOLD feature, the ECO system itself, and other not so obvious. If the larger aux batter is depleted, you will get the Auxiliary Battery MalfFunction message in the cluster, the ECO feature never becomes active, the brake HOLD feature is not available.
I would say that is my understanding this far.
The small battery ( 3 ) works as a backup for the shift selector and other minor electronic components in the vehicle, while the larger one helps to run more features when the car is temporarily OFF: brake HOLD feature, the ECO system itself, and other not so obvious. If the larger aux batter is depleted, you will get the Auxiliary Battery MalfFunction message in the cluster, the ECO feature never becomes active, the brake HOLD feature is not available.
I would say that is my understanding this far.
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Etienne Lau (12-30-2021)