How To Solve Your Mercedes-Benz Auxiliary Battery Malfunction (Singapore)

Recently, world renowned luxury vehicle manufacturer Mercedes-Benz has been at the center of a controversy surrounding the battery configuration in some of their vehicles. Most of the cars made by Mercedes Benz today use a dual-battery system that consists of the primary car battery and an auxiliary battery. Many Mercedes Benz owners have noticed that they will sometimes get an occasional warning message on their dashboard stating “auxiliary battery malfunction” which can be quite scary especially if it happens while you’re actively driving.

The main cause of this problem is generally attributed to a faulty voltage converter and you can also get a computer error message reading “Stop vehicle shift to P leave engine running” when the auxiliary battery begins to malfunction. The problem will become really evident if any of these two messages stays on your dashboard for a prolonged period of time which is a sign that you should begin paying attention to ways that you can resolve the issue.

If you are experiencing any of these error codes, the best way to check if it’s in fact the auxiliary battery is by seeing if the car starts up. If the vehicle is able to startup and operate with limited functionality, it is likely the secondary battery that is causing issues with your Mercedes-Benz. Another way to diagnose a potential auxiliary battery malfunction is by using an OBD scan tool which will allow you to read the detailed diagnostic information about your vehicle down to specific error codes so that you can be sure of what the problem is.

How to fix issues with your Mercedes-Benz Auxiliary Battery

Once you’ve 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 don’t confuse the two terms because they are the exact same component.Once you’ve completed all of these instructions, you can simply follow them in the reverse order to reinstall a new capacitor inside of your vehicle.

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.

What type of Mercedes Auxiliary Battery does my vehicle have?

Mercedes vehicles come with 3 different types of auxiliary batteries which is something you’ll want to keep in mind. Depending on your specific make and model, the location of the battery may vary also which is why it’s important to get that information before attempting to proceed with repair or replacement once you identify an auxiliary battery malfunction.

To check exactly which battery variant is used in your specific vehicle, you will be required to open the trunk and hood. Inside of your trunk you will find fuses if you don’t see a small auxiliary battery nearby, your vehicle does not use a voltage converter. Underneath the hood, you will be able to locate your main battery which can give you a quick insight into the system that your particular model uses. If you don’t see a small auxiliary battery underneath your hood, that means that your car does not have one.

Mercedes-Benz models that are affected by the auxiliary battery malfunction include the following:

  • Mercedes E-Class (W211, S211, W212, S212, C207, A207, ML W166, GL X166)
  • Mercedes C-Class (W204, S204)
  • Mercedes S-Class (W220, W221)
  • Mercedes A-Class (W176, W177, CLA W117, CLS W218, C257)
  • Mercedes Sprinters (W906 Vito, W639, W447)
  • Mercedes B-Class (W246, W247)
  • Mercedes G-Class (W463, G500, G55, G63 AMG)
  • Mercedes C-Class (W205 S205 C205)
  • Mercedes S-Class (W222)
  • Mercedes E-Class (W213 S213 C238)
  • Mercedes GLC-Class (X253 C253)
  • Newer model that is not listed here

All of these vehicles have a mini auxiliary battery that are either hidden or right underneath the hood, dash board or spare tyre compartment so check that area first when you begin to experience issues.

What will happen if the auxiliary battery malfunction appears on the dashboard?

With the natural wear and tear of the auxiliary battery, it might start to have issues which requires immediate attention to prevent it from becoming a major damage. If your car starts up normally but you get warning lights on your dashboard computer screen that shows ‘auxiliary battery malfunction’, that’s when you know you have to replace it.

You will also realize that your auxiliary battery is malfunctioning if your car engine starts and works well, but your car accessories which runs on voltage such as the car audio system, signal lights or your vehicle’s safety feature like PRE-SAFE, Active Brake Assist, ATTENTION ASSIST, Blind Spot Assist, Lane Keeping Assist, Lane Keeping Assist, Night View Assist PLUS, Active LED Lighting are not working.

Additionally, eco start stop and fuel consumption might be affected too. Therefore, whichever signals of malfunction that you are getting, is a sign that it’s time to replace the auxiliary battery.

How much will it cost to replace my Mercedes-Benz auxiliary battery?

At The battery Shop, we offer Mercedes-Benz auxiliary battery replacement service so that you can save money on traditional repair costs. We are also offering comprehensive repair guides for those vehicles owners that feel comfortable in their skill and ability to carry out the repair on their own.

However, keep in mind that if you decide to attempt an auxiliary battery replacement yourself, you are fully responsible for the outcome of the job whether it be a success or a failure. If you attempt the repair and it does not resolve your issue, you might want to bring your vehicle to us, The Battery Shop for assistance.

What should you do when you see the auxiliary battery malfunction indicator on your dashboard computer

The biggest thing that people want to know when they receive the DTC fault code on their dashboard is whether or not the vehicle is still safe to drive. Auxiliary batteries control extension functions in your vehicle like supplying power to your entertainment system, powering the PDC sensors, allowing the radars to work correctly, and providing action for the start/stop function. When you experience an auxiliary battery malfunction, these components and operations in your vehicle will be severely impacted.

However, these components do not often times impact the general mobility and drivability of your vehicle. Still, you don’t want to wait too long to fix the problem as it can lead to more serious issues down the road. Auxiliary batteries like all other car components wear out over time so at some point you will eventually have to replace it.

It’s not recommended to drive when you’re experiencing issues with your auxiliary battery. However, it does not put you in any immediate danger as long as you don’t notice a decline in the overall handling and performance of your car. If it is just a malfunction, you may not need to replace your auxiliary battery at all instead you will only need to correct the on-board computer configuration so that it can read the signals from the battery correctly.

Generally, it is only acceptable to drive your vehicle for about 100 km after you begin to notice issues with your Auxiliary battery as a standard safety precaution to avoid any serious problems. Since the battery itself does not provide power to any main functions in the vehicle, you shouldn’t notice any significant impacts in the area of driving or functionality but if you do, you need to try and solve the issues immediately to avoid causing further damage to your vehicle.

How do I choose the right replacement auxiliary battery?

When choosing the best auxiliary battery replacement for your Mercedes-Benz, there really are no strict requirements. As long as the battery is in a sealed 12V configuration, you should be good to go. Always check your specific vehicle make and model before installing any new auxiliary battery to ensure that it is in fact compatible with your vehicle.

You should be fully prepared to take on Mercedes-Benz auxiliary battery malfunctions by now as long as you’ve taken the time to read this entire article in full. Make sure that you take our advice on how to diagnose the problems, finding the location of the auxiliary battery in your specific vehicle model, how to repair the issue once found, and how to choose the right part for your vehicle so that you can stay on the road safely. Remember to never drive for over 100km after you notice an auxiliary battery malfunction code on your vehicle so that you can avoid damaging your car further.

Reasons to Choose Us For Your Auxiliary Battery Replacement

  • Free island wide delivery (Sit back and relax wherever you are, be it in your office or at home while waiting for our arrival to replace your auxiliary battery)
  • Zero downtime (No more waiting queue for stock order or the need to leave your car at the workshop)
  • Auxiliary battery replacement specialist (We have replaced more than 70% of Mercedes Benz auxiliary battery in Singapore)