The start-stop system was introduced on a number of Mercedes models in 2008.
It’s designed to save fuel by switching off the engine when you come to a stop, then restarting it when you take your foot off the brake pedal.
Unfortunately, this system can malfunction occasionally and stop working due to low voltage.
In this article, I will explain how to fix a Mercedes Start-Stop system that isn’t working and give you some tips on how to avoid this problem in the future. Let’s get to it.
What is the Mercedes Eco Start Stop Feature?
The Mercedes Eco Start-Stop system is an important feature that helps save fuel and reduce emissions.
It works by switching off the engine when you come to a complete stop and then restarting it when your foot comes off the brake pedal.
This saves fuel by eliminating idling time at traffic lights, stop signs, etc.
What Causes Eco Start Stop to Stop Working on a Mercedes?
Technically there are a lot of different things that can cause start stop not to function, but from dealing with a Mercedes with the same problem, it boils down to two possible causes.
1. Bad Battery:
The number cause of failure with the start-stop system is bad battery voltage.
The system requires a certain level of voltage in order to activate.
If the battery has been drained because of other electrical problems, then you will have trouble getting it to work correctly.
Low voltage on a battery can be caused by a bad battery or if you don’t drive enough for your Mercedes alternator to properly charge the battery.
Whether you own an A class, C class, E class, S class , GLA or GLC. I would say 95% of the time that a Mercedes starts to have issues with the start-stop system, it’s because of a bad battery.
Now, let’s look at the other 5% of the time.
2. Outdated Software
In some instances, the problem may be due to outdated software.
If you’ve had your Mercedes for a while, it’s possible that there has been an update to the software in your car that is causing issues with the start-stop system.
This can happen for a variety of reasons, including:
- An update was released by Mercedes, but you didn’t know about it or didn’t get it done because of work schedule changes.
- You updated your Mercedes software but happened to install the wrong version for your specific Merc model.
From my experience, this is a rare cause of the start-stop system not working but it does happen.
How to Fix Mercedes Eco Start Stop that is Not Working?
Now, I have explained that this issue is mainly caused by low voltage or outdated software.
Let’s look at how to fix the eco start stop that is not working on a Mercedes.
1. Replace the Battery
If you never replaced your Mercedes battery in the last 3 years then chances are the battery is bad or on its way out.
Mercedes Batteries typically last anywhere between 3-5 years so if you have not changed your battery in the past 3 years then chances are your battery needs changing and the start stop should start working.
If you recently changed the battery but you don’t drive a lot then it’s possible that the battery is not being charged properly since your battery only charges when you drive.
2. Software Update
If you battery is still in good condition and you drive your Mercedes often enough for it to properly charge the battery then it’s possible that you need to update the software on your car.
Mercedes constantly update vehicles with a newer version of software which is meant to fix this issues and bugs but if you have not updated then are your start stop will still won’t function as it should.
I recommend that you take your car to any Mercedes dealership to have the software updated.
This should fix your problem and get your start stop working again.
Can You Still Drive Your Mercedes When the Start-Stop System Doesn’t Work?
Since the start stop on your Mercedes is only designed to help you save gas you can still drive the car without it.
The only difference is that you will be using more gas than usual but I recommend change your battery when get the time.
Additional Sources
https://www.mbofhenderson.com/how-to/mercedes-benz-eco-start-stop-system/
https://www.autoblog.com/2008/04/06/new-mercedes-benz-a-and-b-class-models-has-start-stop-blueeffie/
https://www.mbeugene.com/service/service-tips-tricks/how-often-to-replace-a-car-battery/