Aucillary Battery malfunction
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Newbie
Joined: Jul 2018
Posts: 14
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From: rhode island
ml350 2015
Auxillary Battery malfunction
Starter the Ml350 2015 (gas) early in tyhe morning with Temp 8F (wc -4) suddenly warning appeared .. check coolant level. After I deleted that another warning came in AUXILLARY BATTERY MALFUNCTION. DID THIS appear because ite is so cold after driving around for 1 hr or late in the afternoon temp went up to 35F . Istarted the car again , it went fine no warning no battery malfunction now batteryand no coolant warning . for the past 3 days everything wrnt fin no warning. Any experienced this . I konw battery is affected by temp.. but wpuld it be this bad. Thanks for comments
Last edited by histo12; Jan 24, 2024 at 03:46 PM.
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Joined: May 2021
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From: US
2008 E350, 2012 ML350, 2014 E350, 2015 ML350
It could be temperature-related, but I would take it as a sign the battery is on its last legs since I bet it did not happen in previous winters, correct?
https://www.batteriesplus.com/produc...IaAry4EALw_wcB
https://www.batteriesplus.com/produc...IaAry4EALw_wcB
Last edited by JCM_MB; Jan 24, 2024 at 03:14 PM.
Member
Joined: Jan 2013
Posts: 190
Likes: 76
2013 ML550 US spec. Air+Offroad pkg
Mine will do the "Check Coolant" message when cold from time to time (full and fresh, so not sure why it does it), so I suspect that is normal so long as your coolant is reasonably fresh and topped off. Cold temp degrades battery voltage, so that could cause the other warning, but if your Aux Battery is more than like 8 years old, I'd replace it because that would be a sign it is getting weak. Batteries on the W166 last longer than regular cars probably due to the OE quality (Bosch I believe is the real brand) and most importantly, they are in a climate controlled environment, not under the hood (main battery under the right seat, aux in the rear). Replace both main and Aux at same time...they tend to have similar lives, and MB is real sensitive to voltage variations.
Thread Starter
Newbie
Joined: Jul 2018
Posts: 14
Likes: 2
From: rhode island
ml350 2015
Mine will do the "Check Coolant" message when cold from time to time (full and fresh, so not sure why it does it), so I suspect that is normal so long as your coolant is reasonably fresh and topped off. Cold temp degrades battery voltage, so that could cause the other warning, but if your Aux Battery is more than like 8 years old, I'd replace it because that would be a sign it is getting weak. Batteries on the W166 last longer than regular cars probably due to the OE quality (Bosch I believe is the real brand) and most importantly, they are in a climate controlled environment, not under the hood (main battery under the right seat, aux in the rear). Replace both main and Aux at same time...they tend to have similar lives, and MB is real sensitive to voltage variations.
Member
Joined: Jan 2013
Posts: 190
Likes: 76
2013 ML550 US spec. Air+Offroad pkg
Mine was the small battery with insertable leads under the right rear tail-light. Took rear of car apart to get to so not cutting anything. I've heard that MB uses different batteries at different times and puts them in various locations based on the equipment on the car, so probably best to locate it before you buy a new one. Id check under the tail light first...I think you can stick your hand down there via the access panel to see if it is there...probably need some disassembly to actually remove it...it has a bracket holding it down, hard to get to thru the access door.
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From: Toronto
2013 Mercedes GL350 Bluetec (X166) & 2019 Mercedes A220 (W177) & Retired 2008 Mercedes C300 (W204)
See this thread on the battery replacement. https://mbworld.org/forums/m-class-w...x-battery.html
As previous post mentioned, double check your battery size before you buy it.
You should be able to open the access cover on the right side of the cargo area and get a phone to snap a picture of the battery in there or just open it up and get a good look (you would have already done about half the work to get access to it).
As previous post mentioned, double check your battery size before you buy it.
You should be able to open the access cover on the right side of the cargo area and get a phone to snap a picture of the battery in there or just open it up and get a good look (you would have already done about half the work to get access to it).
