Mercedes Benz Auxiliary Battery Malfunction

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What Does An Auxiliary Battery Malfunction Warning Mean

Auxiliary Battery Malfunction: Mercedes E Class W212 Replace

Generally speaking, an auxiliary battery malfunction warning means that your Mercedes auxiliary battery isnt charging as it should. This can happen for several reasons, but the most common cause is a problem with the cars alternator.

The alternator is the component that charges both the main battery and the auxiliary battery while youre driving. If theres something wrong with the alternator, it can cause the auxiliary battery to become discharged. Discharged batteries are no good because they cant hold a charge and eventually die.

Auxiliary Battery Malfunction Mercedes

Auxiliary Battery Malfunction is a common error message when the Mercedes-Benz auxiliary battery fails. Mercedes-Benz uses an aux battery to operate the transmission and critical accessories in critical situations.

The most common issue that triggers this error on Mercedes-Benz vehicles is a dead auxiliary battery .

In most cases, to fix Mercedes-Benzs auxiliary battery malfunctions, you must replace the auxiliary battery. This repair takes about thirty minutes.

The auxiliary battery location varies between models.

The auxiliary battery is typically located in one of these locations:

  • the left side of the dashboard
  • in the engine bay
  • under the front passenger seat.

In some models, the auxiliary battery may be in the engine bay , under the passenger seat , trunk, and behind the drivers seat we will go into more detail later.

This guide will explain everything you need to know about the auxiliary and replace it yourself for under $100.

Newer Mercedes-Benz cars and SUVs have two batteries:

  • Main battery System battery, starter battery, or G1. Its primary function is to start the engine and be the primary power source for all electrical systems.
  • Auxiliary battery . Also known as the secondary battery, backup battery, aux battery, or G1/7. Usually an AGM battery. Typically specs: 12V, 1.2Ah, 170 A. Supplies power if the main battery voltage is low. Part number: 000000004039

What Is The Auxiliary Battery For Mercedes

It is a backup power source that supplies the electric current to the electronic components of a car. Also, it supports the central power system and provides energy to the infotainment system.

Moreover, it helps in the start and stops procedures of these vehicles. These are present in the hood compartment and perform multiple functions.

It becomes supremely active while the central power system becomes dead. It keeps the navigation system on throughout without sudden dropping.

However, it is smaller than the standard equipment but has a continuous flow of high voltage. It is a power hub for the accessories and keeps them intact without any internal damage.

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What Does The Auxiliary Battery In A Mercedes

Your Mercedes-Benz C 300s auxiliary battery is an integral part of your vehicles operation. Without it, your instrument cluster, dashboard error messages, and other electrical components such as GPS will not turn on, impacting the overall driving experience.

Keep reading to learn more about auxiliary batteries, auxiliary battery malfunction C 300, causes to malfunction, and fixing your C 300 auxiliary battery.

How Do I Fix My Mercedes Auxiliary Battery Malfunction

c quy ph Mercedes CLA (AUXILIARY BATTERY MALFUNCTION)/c quy chính ...

No one likes to see an error pop up on their carâs dashboard, especially when it warns of malfunctions or electrical errors.

The Mercedes auxiliary battery malfunction usually pops up when the battery dies, and you can fix it with a simple replacement. While this is the issue 9 times out of 10, the other 10 percent gets frustrating fast.

In this article we explain what the malfunction pertains to, how to diagnose a bad aux battery, and how to swap it out . Weâll also touch on what you can do if the problem continues after installing your new battery.

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What Is The Auxiliary Battery

Every passenger vehicle comes equipped with a 12-volt battery that is used to start its engine. The same is true with the Mercedes-Benz lineup of vehicles. However, the German automaker has also installed a second battery in vehicles since the early 2000s.

This second battery is known as the auxiliary battery. Its a smaller version of the battery that starts the vehicle. In some cases, Mercedes refers to it as a capacitor because of its smaller size.

This auxiliary battery serves as a backup to the main car battery. Depending on which Mercedes model its installed in, it serves a different purpose. In some cases, the auxiliary battery or capacitor is used to power up the electrical accessories, such as the infotainment system or radio. It can also be used for the engines stop-start system operation.

As with the main car battery, this secondary battery gets charged any time that the engine runs. It also has a similar lifespan, ranging from four to six years. Once it can no longer hold a charge, you might see a warning light illuminate on the dashboard or infotainment system.

How Much Does A Mercedes Benz Auxiliary Battery Cost

These are cost-effective power sources with high efficiency and durable work performance. However, you can purchase them for around $45 to $55.

The prices change according to the selling portals and the demand for the equipment.

However, you can buy them online with authentic warranty policies and a standard manual.

They have a maximum cost of around $49 to $55. But, a few portals sell them in affordable price ranges.

You can purchase it at a minimum cost of around $45 to $47 with extraordinary results and a standard lifespan.

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What Type Of Mercedes Auxiliary Battery Does My Vehicle Have

Depending on your Mercedes make and model, there are three types of auxiliary batteries. Their location also varies depending on the car’s make and model.

So, how do you know which auxiliary battery type you have? Simple! Open your car’s trunk and hood. It would be best if you located an auxiliary battery alongside some fuses when you open the trunk. You should also see a small auxiliary battery underneath the hood.

How Much To Replace Auxiliary Battery On Mercedes Benz

Mercedes Auxiliary Battery Malfunction **EASY FIX!**

Many people find it challenging to replace the auxiliary battery of their Mercedes Benz. It is a backup voltage source that facilitates the cars start/stop, and works with a running engine.

How much to replace Auxiliary Battery on Mercedes Benz? You can replace the Auxiliary battery on a Mercedes Benz for around $210 to $325 by purchasing it for $45 to $55. However, the Mercedes service station does its alteration for $50 to $310 labor costs you from $55 to $110 and completes the procedure in 22 to 25 minutes. It is a rechargeable battery and requires replacement after 7 to 8 years, and its malfunctioning shows a warning sign on display and affects the GPS, radio, and entertainment system.

In addition, a dead power source does not affect the vehicle immediately but produces long-term internal electric faults. It takes around 2 to 6 hours to recharge and can start an engine.


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Are There Other Factors That Affect My Batterys Performance

Along with vehicle usage and battery quality, youll consider several other factors that can impact your batterys performance. Taking your car on short rides can put stress on the battery, and accidentally leaving your lights on can cause a power drain. If you use your electronics or lights without turning the car on, youre putting stress on the battery. Extensive idling, a loose fastener, and not having your vehicle serviced regularly are also factors that will reduce your batterys performance.

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Find The Symptoms Of Auxiliary Battery Malfunction In Mercedes

  • 1. Find the Symptoms ofby Walnut Creek
  • 2. Modern cars likeMercedes-Benz havetwo batteries toprovide the necessarypower such as Main battery Auxiliary battery
  • 3. Auxiliary battery is asecondary battery thatgets power from themain battery toperform all the tasks.
  • 4. When you start/stopthe engine, it preventsthe electricalcomponents fromdropping.
  • 5. If the auxiliary batteryof your Mercedes-Benzis damaged, you willnotice many problemssuch as The Dashboardshowing errormessages Failed instrumentcluster Turning off the GPS
  • 6. When the auxiliarybattery is failed, youwill notice the belowsymptoms in Mercedes-Benz.
  • 7. Thus, the battery ofyour car needs theright amount of fluidto run the engineefficiently.
  • 8. If the fluid is leaking,then it will affect thebattery functions andneed immediatereplacement.
  • 9. When the auxiliarybattery of your car isfailed, the engine doesnot crank after longtries.
  • 10. Due to this reason, youhave to jump off thecar and die back outafter being turned off.
  • 11. To function all thecomponents of the car,the battery needs to befully charged.
  • 12. Due to the lack ofbattery charge, manycomponents of the carstop functioning andactivate the batterylight on the dashboard.
  • 13. Generally, themalfunctionedauxiliary battery canaffect several electricalsystems such as: Radio andentertainment system PDC sensors and GPS Lane-keeping assist Blind spot assist Start/stop functionality
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    How Often Should You Have Your Car’s Auxiliary Battery Checked For Problems And Malfunctions

    How often you use your car, the driving you do, and the climate in which you live all play a role in determining how often you should get the auxiliary battery in your car checked for problems and malfunctions.

    If you drive in a manner that involves a lot of starting and stopping, or if you have a habit of listening to music when the engine is off, the battery in your vehicle will probably wear out more quickly. It will need to be replaced more frequently.

    On the other hand, it is generally recommended that you have your auxiliary battery checked once every two years or so, at the very least. You can help ensure that your vehicle will start easily and continue to operate reliably for many years to come if you pay attention to the condition of your battery and have it serviced whenever necessary.

    How To Fix Issues With Your Mercedes

    Auxiliary Battery Malfunction 2009 W216

    Once youve found the root cause of the problem, the next step is finding out how you can fix the auxiliary battery in order to restore complete functionality to your vehicle. In newer model Mercedes-Benz vehicles, the Mercedes auxiliary battery is located inside of the front footwell of the passenger seat located near the top.

    To access the battery, you will need to completely detach all connecting parts in addition to removing the carpet so that you can gain possession of the battery. The fastening screws securing the battery to the storage component are outfitted to be removed using a 10mm socket which makes it really easy to access.

    As a safety precaution, you should also remove the connectors on the primary car battery before removing the auxiliary battery to ensure that no shortages or sparks occur. After all of the above steps have been completed, you can begin removing the voltage converter by peeling back a few small plastic tabs. Another common name for the voltage converter is the capacitor so dont confuse the two terms because they are the exact same component.

    If you own any of the above models, you can also call The Battery Shop to replace the auxiliary battery in order to let them check it out so that you can be safeguarded from any potential issues which may arise with the Mercedes auxiliary battery inside of your car.

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    Why Does Auxilary Battery Malfunction Come Up

    When the auxiliary battery fails to hold a charge to recharge, you will get an error message such as auxiliary battery malfunction or, in 2015 and newer models, stop vehicle shift to P leave engine running warning message. These two error messages are common for Mercedes-Benz cars, and other than the error message, the vehicle usually runs and drives fine.

    If the car runs and drives fine, the problem is an auxiliary battery, but you keep seeing the auxiliary battery malfunction error on the dashboard.

    We have seen Mercedes-Benz try to read the codes with a generic OBD-II scanner, but no fault codes come up. Using a generic scanner, you will not find fault codes that indicate a bad auxiliary battery since generic scanners cannot read Mercedes-Benz-specific fault codes.

    You will know that the secondary battery is at fault because the car will still turn on, and some functions will work. The auxiliary battery does not affect the cars mechanical functions.

    C350e Auxiliary Battery Location

    Deleted member 126969


    It has a large AGM 12V battery at the back of the car, left side, under the boot floor.Here you go, a video on how to replace it:It also has another, smaller, 12V lithium battery lurking somewhere in the passenger compartment which could be the one the error referred to?. ePC calls this smaller one the Auxiliary battery, so that sounds favourite.Item 200 on this page:

    Deleted member 126969

    s212 Hybrid

    Chris-S said:I don’t know…but I can’t imagine that the 12V batteries wouldn’t be maintained from the HV battery under all normal circumstances. Bear in mind the car doesn’t have a conventional alternator and relies on the HV battery to run the inverter that generates the 12V. If you left the car with a low HV state of charge, it might have decided to let the 12V take it’s chances for a bit?? Really don’t know, just guessing.I’d be inclined to charge the HV battery then just keep an eye on it for a bit. Or just drive it a while. Not so easy these days though

    Deleted member 126969


    rayasun said:Hm. I had bought a 350e over 6 weeks ago, I had the AUX warning and got it fixed by the trader. I don’t the warning anymore, however the battery charges fully and it says it car can go up to 14 miles by using electric.

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    What Is An Auxiliary Battery Malfunction In A Mercedes

    Its no secret that the Mercedes Benz is a marvel of a machine. In fact, its one of the handful of modern automobiles with two batteries. The main battery, located under the hood, powers the engine. The auxiliary battery, located in the trunk, powers the Mercedes electrical accessories like the radio, navigation system, and lights.

    An auxiliary battery malfunction warning means something is wrong with your cars auxiliary battery. In todays post, well take a deep dive into what an auxiliary battery malfunction is, what it means for your car, and how you can fix it. But first, what is an auxiliary battery?

    An Auxiliary Battery For Mercedes Benz: What Is It

    How to fix Auxiliary Battery Malfunction on Mercedes S550 w221

    Depending on the model, year, and several other parameters, there are two distinct kinds of auxiliary batteries, also known as Mercedes secondary backup batteries, in Mercedes-Benz vehicles.

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    For instance, the E class W211 S211 W212 S212 C207 A207 ML W166 GL X166 C class W204 S204 S class W220 W221 A class W176 W177 CLA W117 CLS W218 C257 Sprinter W906 Vito W639 W447 G class W463 G500 G55 G63 AMG cars have the small auxiliary battery located at the luggage compartment or under the front side upper cover at driver side.

    To determine which battery is used in your Mercedes, you must first open the hood and trunk . In the trunk, this component is typically found close to fuses. If, after checking these two locations, you were unable to find a small auxiliary battery, your car is likely using a voltage converter.

    The stop-go function, among other things, is powered by the auxiliary battery, which controls and runs them. If the auxiliary battery fails, none of these features will operate.

    Other models, such as the C class W205 C200 C220 C250 C300, have an auxiliary battery as well, however it functions more like a tiny module ballast, also called a voltage converter, and serves the same function as other types of batteries: to power up and operate extra automobile equipment.

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    How Long Do Mercedes Car Batteries Last

    While every car is slightly different, most batteries last for an average of three to four years. There are several factors that will help decide whether your battery lasts closer to three or four years. Your Mercedes battery life depends on the battery quality and how often you use your vehicle. If you have a newer Mercedes, the battery can often last five years at a minimum. However, its possible to go over five years without worrying about replacing it.

    Is It Safe To Drive Mercedes With An Auxiliary Battery Malfunction

    The vehicle does not stop due to malfunctioning or dead auxiliary equipment. But, automobile specialists suggest drivers for avoiding these conditions.

    Moreover, it does not affect the standard performance of a car, but its malfunctioning results in the failure of other electronic components.

    It produces dangerous complications by putting additional tension on other charging parts.

    Finally, as a result of malfunctioning, it cannot supply enough electrical energy to the radio, GPS, and other systems.

    These gadgets charges on the standard system. But, they provide backup voltage to several appliances.

    During their non-working conditions, these gadgets get the voltage from the central power hub. The power source drains quickly, and the engine cannot start.

    Resolve the problems by accessing the errors or replacing this gadget within 1 to 3 hours of malfunctioning.

    However, it never results in accidents or unnecessary swaying because the vehicle does not depend on this equipment.

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    Replacement Instructions For Your Mercedes

    Here are the steps needed to replace an old Mercedes-Benz E 350 auxiliary battery with a new auxiliary battery. For this task, you will need a 10mm wrench.

  • Remove the housing that covers the auxiliary battery.
  • Use a 10mm wrench to loosen the ground line bolt and remove it from the battery.
  • Remove the positive ground line from the battery.
  • Loosen the battery’s hold down bracket nut and fold the hold-down bracket back.
  • Remove the old auxiliary battery.
  • Install the new auxiliary battery, completing all of the above steps in reverse order.
  • Reinstall the positive line onto the positive battery terminal and reinstall the negative line to the negative battery terminal before reinstalling the housing.
  • Perform a quick 5-minute test drive to ensure all of your electrical components are working. Pay attention to LED lighting, entertainment center radio, and safety features such as Lane Assist, Blind Spot Assist, and Active Brake Assist.
  • Do not forget to remove your Mercedes-Benz E 350’s primary car battery’s connectors before removing the auxiliary battery. This is very important. Failure to do this may result in shortages or sparks.

    All in all, one can easily replace the whole Mercedes-Benz E 350 auxiliary battery, even with moderate mechanical skills. Be sure to seek all replacement parts from the Mercedes-Benz national store. If you are looking for a replacement auxiliary battery, please consult with your Mercedes-Benz E 350’s owner’s manual for the exact one needed.

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