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2013 GLK with "Auxiliary Battery Malfunction" message???
I have a 2013 GLK 350 with about 53k miles. Today, while sitting in line to pick the kids up from school she got a message that said "Auxiliary Battery Malfunction". Other posts for other vehicles say that the battery is ONLY for certain things, like braking or shifting to park in case of an emergency. Any insights? Where is it located and how hard is it to replace? Should I even worry with it if it doesn't come back on?
Take it to your dealer and ask for a "good will replacement" - if they say no, call MB Customer Service and politely ask them - the tact to take is this - the battery is NOT a mileage/age issue - it should be a age/age issue - and three years is damn too soon !
Please see my original reply - (1) MB Roadside Assistance "replacement" prices are set by their dispatching dealer - and some areas free install , most not, and some areas replacement battery is same cost as walk-in to the parts counter, most not and are higher.
On the guy with the "E" - I guess he didn't call MB Customers Service after his dealer said "no" - and you are very right - you don't get the prize if you don't try.
This is a 2yr old GLK - and again "life" of a battery is by time, andnot by miles - and YES there should be a "goodwill" from the dealer and/or from MB in this case - if you "try" because it's the "right thing to do"
Let's see. My owners manual talks about the main battery in many places. It talks about the battery in the remote, even about what to do if you swallow it! It talks about replacing the battery in a garage door remote if you can set home link. Possible battery failure in the tire pressure sensing sensors (TMPS) is covered. But that gives a "sensor missing" display.
Nope, can't find anything about a second battery. What does it do and where is it?
Possibly, the 2010's didn't need it for all that "EXTRA" stuff. But, I would still like to know why and where it is used. So if anyone has an 'Owner's Manual' that talks about an extra battery, could you share a little insight?
they added them into to 2013 and up for the eco start stop function. its a buffer battery. lift up the lid in the rear cargo area and remove the cover. its down in there and really simple to replace.
Thanks for the info. Interesting that the start -stop is driven by the EPA to improve millage but ecologically costs a lot of lead, weight, battery mfg, charge energy, controller and recycle stuff. Forgive them for their hearts are true but their brains are busted!
If the battery only supports the start/stop function and it does in fact completely fail, will the truck just NOT kick in start/stop?
Sometimes it doesn't anyway as you probably know depending on electrical load, etc. Is the truck smart enough to sense that the battery is dead and just NOT shut down in traffic?
And for the record, still haven't taken it to the dealership. Truck needs tires and in my opinion, bad tires lead to assumptions about poor maintenance. Since I started changing my own oil, filters, rotors, pads, etc and don't go to the dealership anymore, I want the truck in peak shape when I go in. And since my wife drives it, it doesn't lend me many opportunities to get tires, visit dealership, etc.
Last edited by shawnmichael; 02-04-2015 at 09:37 AM.
Reason: Status update last paragraph
So I finally stopped by Monday this week (MB of Mobile, AL) while I was talking to Nissan about my car (don't buy a fricken Altima even if it is only your work car). I spoke with my regular service advisor who was open to trying to get it done as a courtesy but said I needed to speak with the service manager who was busy at the moment. I finally spoke with him and he agreed to replace the battery, saying in a roundabout way that it was a common problem. He told me to have her bring it in, sooner is better.
So she took it by there Wednesday and after looking at it, they said it was a relay, not the battery that had failed. They ordered it and said Friday or Monday it should be ready. Still haven't heard back so not sure if the problem is resolved but that is my update.
In case anybody else has the issue, be careful not to replace the $140 (on eBay) battery without being prepared to replace a relay as well.
When I have the truck back and the final update, I'll try to provide information on exactly what relay had failed.
So .... I picked it up this afternoon and the part is:
000-982-20-23 Relay
There is no price listed and I can't find it online anywhere so I have no idea where one would get it other than the dealership and no idea how much it will cost.
Coincidentally, they left the inside panel off of the passenger taillight so I assume that that is where the relay is located (in case somebody else needs to be pointed in the right direction).
Since the message was intermittent I have no idea whether or not it actually fixed the problem but I do trust that it will since it says they tested the battery and it tested good. Hope this helps somebody else out there.
Last edited by shawnmichael; 02-23-2015 at 11:50 AM.
I have a 2013 GLK 350 with about 53k miles. Today, while sitting in line to pick the kids up from school she got a message that said "Auxiliary Battery Malfunction". Other posts for other vehicles say that the battery is ONLY for certain things, like braking or shifting to park in case of an emergency. Any insights? Where is it located and how hard is it to replace? Should I even worry with it if it doesn't come back on?
I just had it done wish I read this post first, it was $250 on my 2013 GLK under 4 years old with 54,000 miles at Auto Nation in Wesley Chapel, Fl.
So .... I picked it up this afternoon and the part is:
000-982-20-23 Relay
There is no price listed and I can't find it online anywhere so I have no idea where one would get it other than the dealership and no idea how much it will cost.
Coincidentally, they left the inside panel off of the passenger taillight so I assume that that is where the relay is located (in case somebody else needs to be pointed in the right direction).
Since the message was intermittent I have no idea whether or not it actually fixed the problem but I do trust that it will since it says they tested the battery and it tested good. Hope this helps somebody else out there.
The battery relay's function is to connect the aux battery to the main battery in order to keep it charged. There is a circuit that detects the state of charge of the main battery and connects the aux battery to keep it topped off. If the relay fails or is intermittent, the aux battery wont get topped off and will trigger the alarm. If it happens frequently, it will reduce the life of the aux battery or kill it completely.
The life of that battery also depends how much you use the ECO function. Its main draw is an electric pump that keeps the transmission pressure up when the engine shuts down at a stop. If you don't use ECO, and the battery relay is working, the aux battery will stay topped up and last a long time.
Take it to your dealer and ask for a "good will replacement" - if they say no, call MB Customer Service and politely ask them - the tact to take is this - the battery is NOT a mileage/age issue - it should be a age/age issue - and three years is damn too soon !
I tried this tact on on my GLK and they were unpleasant about it that I even asked. Typical. At the local Auto Nation recently had transmission fluid change, sat and watched them do it through the glass wall, was on the hoist less than an hour, the invoice charged 2 hours labor. I would call that thievery, they know it. They're great cars but they love to rock you.
Wife's '13 GLK350 started notifying us of the "Auxiliary Battery Malfunction". Since then, she has been turning off the "Eco" every time she starts the car until i had some time to look at it today. Located it just now and found the following with the aux battery in the trunk compartment:
- with leads connected it gives 12V;
- without pos lead connected, it gives 12V;
- between neg post of Aux battery and disconnected pos lead, it gives 2V.
Engine off in all three cases.
With engine on, i get:
- between neg post of Aux battery and disconnected pos lead, it still gives 2V - which tells me that the battery is not being charged, unless there is some smart charging tech that only supplies 12+V if it senses the connection
- between neg post of Aux battery and pos lead at the relay (see pic), i get 12V.
The above seems to tell me that the battery is not being charged, even though it gives off 12V (which is strange as it should, ultimately, drain to ~0V over time), so the battery may hold the charge fine but is not being charged as the relay may have broken a short time ago? Now I am just assuming things.
I am trying to figure out if the Aux battery is bad OR if its a bad relay (or both, but far fetched). Not an electrician but..
Wife's '13 GLK350 started notifying us of the "Auxiliary Battery Malfunction". Since then, she has been turning off the "Eco" every time she starts the car until i had some time to look at it today. Located it just now and found the following with the aux battery in the trunk compartment:
- with leads connected it gives 12V;
- without pos lead connected, it gives 12V;
- between neg post of Aux battery and disconnected pos lead, it gives 2V.
Engine off in all three cases.
With engine on, i get:
- between neg post of Aux battery and disconnected pos lead, it still gives 2V - which tells me that the battery is not being charged, unless there is some smart charging tech that only supplies 12+V if it senses the connection
- between neg post of Aux battery and pos lead at the relay (see pic), i get 12V.
The above seems to tell me that the battery is not being charged, even though it gives off 12V (which is strange as it should, ultimately, drain to ~0V over time), so the battery may hold the charge fine but is not being charged as the relay may have broken a short time ago? Now I am just assuming things.
I am trying to figure out if the Aux battery is bad OR if its a bad relay (or both, but far fetched). Not an electrician but..
Does anyone know what is likely the issue?
Thanks in advance.
The Aux relay has logic to detect main and aux battery voltage and it can fool you. 12 volts is too low for the Aux battery if you aren't using ECO. Mine runs 12.9 - 13.2 and I don't use ECO at all. Sounds like your relay has failed, but it could be a bad battery that is telling the relay not to connect it to the charging circuit. I would pull the aux battery and have it checked. If its good and just needs a charge, that would indicate that the relay probably isn't closing to connect it to the main circuit for charging. If the battery tests bad and you replace it, you can still have a bad relay that was the root cause of the battery failure. Once you have a known good battery with a good charge, you can monitor the voltage and see if it stays up or drops off, indicating a faulty relay. Troubleshooting the relay is a pain because of the sensing logic it has. I believe it even has a timing circuit to make it wait for a while after the main battery voltage is up before allowing the aux battery to charge.
That makes sense. Thanks. I'll have the battery checked out and report back what I find.
BTW, i should have measured the voltage more accurately as i used an analog voltmeter and the scale reads from 0 - 50V, so it is difficult to determine anything between 11 and 13V. I'll use a digital meter and check again. Thanks for the advice.
01-09-2015, 08:02 PM
