Mercedes-Benz won’t start – causes and how to fix it

Mercedes-Benz won’t start - how to fix it

Mercedes is one of the most prominent brands on the market right now as Mercedes cars tend to set benchmarks for other brands to follow. Whether it be an A-Class or the top-spec Maybach S-Class, a Mercedes is a car that oozes quality, refinement, and technology, and is also on the very top end of the safest cars on the market.

However, no car is without fault which means that there are plenty of things that can go wrong even with a Mercedes. As these are so complex, countless things can go wrong, but arguably the worst ones are when you can’t even start the car up. This means that your luxury Mercedes can also leave you stranded, but most of these issues can indeed be fixed.

So, if your Mercedes-Benz won’t start, we will tell you what to do! The reasons why your Mercedes refuses to start are usually associated with the battery, the fuse, the relays, issues with the fuel system, issues with the starter motor, spark plug issues, alternator issues, or a weak key fob battery.

We will now go in-depth about all of these issues and tell you how you can fix them. So, if your Mercedes won’t start, be sure to read this article!

Battery Issues

Numerous battery issues can cause your Mercedes to refuse to start, but the most often ones are a weak battery, a depleted battery, or corrosion on the battery terminals. The best thing you can do is to test the battery with a multimeter, if the battery reads between 12 and 13 volts, all is ok with your battery, if not, you need to replace it. In case of corrosion, you need to clean the corrosion away from the terminals with baking soda after disconnecting the battery.

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Fuse and Relay Issues

Your fuses and your relays are tasked with keeping your electrical system safe in case of a short circuit or if the battery sends too much energy. This means that these ought to be checked right after checking your battery as a burnt fuse is often a reason why a car won’t start. While replacing the fuse, be sure to replace it with a fuse with the same amperage.

Fuel System Issues

Another fairly common reason why a car won’t start is when the fuel pump fails. As such, be sure to turn on the ignition (if possible) and you should be able to hear the fuel pump turning on. If you can’t hear anything, your fuel pump is dead. Also, if your car has a Schrader valve adapter, you should test to see if your fuel tank PSI levels are around 60PSI, if not your fuel tank pressure is not steady and thus can cause your car not to start or to stall when started.

Starter Motor Issues

Some Mercedes mechanics will tell you that a starter motor is designed to last between 100,000 to 150,000 miles, so if your car refuses to start with 100,000 to 150,000 miles on the clock, this could the reason. When turning the key in the ignition, if you hear clicking sounds without cranking the engine, your starter motor is likely to blame and should be replaced.

Spark Plug Issues

The spark plugs are not often defective in most cars, but the plug connections are. The best thing to do here is to inspect your spark plugs when you can and if one of them is loose, be sure to reconnect it properly. Moreover, if one of the connections is bad, you will have to replace the associated part.

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Alternator Issues

The alternator is tasked with charging your battery while driving which means that whenever a battery is depleted but isn’t all that old, your first point of concern should be the alternator. Even if you replace the battery, it will get depleted again because a faulty alternator will not be able to charge it. If it indeed fails, replacing it with a new one is always going to be the best option as you don’t want your car to die on you.

Weak Key Fob Battery

If your Mercedes comes with keyless technology, your key fob needs to have a sufficient battery so the car can make sure the key is inside the vehicle when wanting to start the car. If your battery is weak, the car will not be able to detect the key and thus will not let you start the car. To remedy this, you can either replace the battery or if your key has a blade, just start the car up manually.

FAQ Section

Are Mercedes cars reliable?

Mercedes cars are usually in the average section of the car market when it comes to reliability which is rather a shame as they are really superior cars in many other aspects. This is because Mercedes makes complex cars that come with all kinds of tech and features and there are simply too many things that can go wrong.

Moreover, Mercedes is a brand that likes to innovate which means that they often come out with new technologies that are sometimes not in the very latest stages of development. If you combine that with the fact that new Mercedes car owners tend to keep their cars until the warranty runs out means that Mercedes isn’t too fussed about making the most reliable cars on the market.

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How long can a Mercedes last?

One thing is for certain, Mercedes does make cars that can last a really long time as that is something most Mercedes owners love about Mercedes. You can find Mercedes models with upwards of a million miles on the odometer which is impressive.

Sure, modern-day Mercedes models are not built to last as long as that, but they should be able to do 200,000 miles if take decent care of them.

What to do when a car leaves you stranded?

If you can’t start the car up and continue driving, be sure to turn on your hazard lights, move away from the road, turn your wheels away from facing the road, call for help and stay inside the car. If you have a high visibility vest, be sure to wear it and also be sure to place a warning triangle where other motorists can see it.

Try to always be visible to other motorists which means that you shouldn’t park mid-corner if that is not necessary.

Reasons your Mercedes might struggle starting

Related Terms Mercedes-Benz won’t start

Mercedes-Benz Not Starting

Why is my car not starting

Why isnt my car starting

Car not starting

Car wont turn over

Engine wont turn over

Starter wont turn engine over

Applicable Models

Mercedes-Benz Models

A Class



E Class













Marko Mikulic

Why do you love writing about cars? I love writing about cars as cars are a huge personal interest of mine. I was raised in a car enthusiast community and ever since I was young, I always wanted to do car-related work.

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