What Causes Auxiliary Battery Malfunction in a Mercedes?

You were driving down the road; when the dash of your Mercedes suddenly displayed a message that reads- "Auxiliary battery malfunction". The very thought of receiving a message like this gives you a headache... doesn't it? But, don’t worry… This article will explain everything you need to know about this bizarre message; like what exactly does this message mean and what can you do to get rid of it. So, let’s get started.

What Does "Auxiliary battery malfunctions" Message Mean on Your Mercedes?

The message simply means – there is something wrong with the auxiliary battery of your Mercedes. In case you are wondering what exactly an auxiliary battery is and what role it plays; please keep reading. In essence, an auxiliary battery is nothing more than a backup to the main battery.

As far as its function is concerned, it usually depends on the model and makes of the vehicle in which it is installed. It can power the start and stop system of the vehicle. Your car's infotainment system and other electrical equipment can also be powered by it. A defective auxiliary battery will affect your Mercedes' drivability, so you should keep an eye on that.

You should not ignore anything that indicates auxiliary battery failure in your Mercedes, such as the appearance of a message that reads- 'Auxiliary battery malfunction' on the dashboard. Well, now that we know for sure that; a problem with the auxiliary battery triggers the "auxiliary battery malfunction" message, let's discuss the reasons why your car's auxiliary battery can go bad.

What Causes Auxiliary Battery Malfunction in Mercedes?

There are countless reasons why the auxiliary battery of your Mercedes can go bad. Some of them are listed below;

Battery is old

If the auxiliary battery of your car is not functioning properly, it is probably getting old. We all know the purpose of a battery is to store electricity. But, have you ever wondered how does it do this? Well, the answer lies in its unique chemical makeup. Batteries are made from a variety of chemicals. The problem with these chemicals is that they can degrade over time.

Chemical degradation due to aging can render the auxiliary battery of your Mercedes useless. And, when the onboard diagnostic system of your Mercedes finds out that the battery is not working the way it usually does, it will warn you about the problem by displaying an "Auxiliary battery malfunction" message on the dash.

Faulty main battery

Another problem that can result in auxiliary battery malfunction in a car is a defective main battery. As you would have read before, the purpose of an auxiliary battery is to act as a backup for the main battery. So, obviously... problems with the main battery will put a lot of stress on the auxiliary battery; and may even cause its failure.

So, if you notice an "Auxiliary battery malfunction" message on the dash of your Mercedes, have someone check on its main battery. And, if the main battery is faulty, consider replacing it right away.

Bad charging system

Mercedes' main battery and auxiliary battery both rely on the same charging system. For those who don't know, the charging system generates electrical energy to charge the battery. It is made up of several components like the alternator, voltage regulator, wires, etc.

Problems with your car's charging system can damage both the main and auxiliary batteries. That’s why if you have a feeling that there is something wrong with the charging system of your Mercedes, take it to a nearby car service center so that the exact cause of the problem can be identified and repaired.

What Should You Do If Your Auxiliary Battery Is Faulty?

It is unsafe to drive a Mercedes that displays the message "Assistant Battery Malfunction" on its dashboard. So, if your Mercedes is displaying this warning message, have its auxiliary battery tested by a technician. And, if the battery has flaws, just install a new one.

Wrapping Up

The bottom line of this discussion is- an auxiliary battery is one of the most important parts of your Mercedes. If for some reason, it goes bad, you will encounter many drivability problems. For instance, you might not be able to bring your car engine to life if its auxiliary battery is dying. That's why if you notice an "Auxiliary battery malfunction" message on the dash of your Mercedes, rush to a nearby car service center immediately.

DreamCars Auto Repair is a specialized European Auto Repair shop and parts store in the High Desert of Hesperia, CA. It is a AAA approved facility & the only authorized Bosch service center in the High Desert with highly trained ASE