Reasons Your Mercedes Won’t Start

Posted on June 19, 2020 by Carson Wileman
Mercedes Starting Issue

There are several reasons why your Mercedes may not start. Your entire vehicle may seem completely dead, from the security system down to the mechanical components. The engine may fail to run, or a key may not turn in the ignition. Worst, your Mercedes may start but then suddenly stall in the middle of traffic without restarting.

There are a variety of different signs and even more potential causes. In this article, we’ll take a look at some of the reasons why your Mercedes won’t start, as well as some useful troubleshooting guides.

When Your Mercedes isn’t Starting…

There are a number of reasons your Mercedes may not start, and a few ways you may discover it. Some of the things you may notice are:

  • fuel gauge reads low
  • nothing happens when you turn the key in the ignition
  • key won’t turn in the ignition
  • you can’t insert the key into the ignition
  • the car cranks but doesn’t start
  • the car engine to smoke
  • the car starts but abruptly stalls
  • your engine misfires multiple times
  • the battery is dead
  • your engine makes strange noises
  • the lights come on but nothing else happens

Engine Cranks but Won’t Start

The most common sign that your Mercedes won’t start is when the engine cranks but doesn’t turn over. Let’s take a closer look at the reasons why this happens:


You’d be surprised how many drivers let their fuel all but run out. Some drivers try to eke out their fuel for as long as possible only to be caught short, while others are caught out by a faulty fuel gauge. Fuel problems can also cause your engine to crank but not start when you have used the wrong fuel type or fuel that is contaminated. A blown fuse can stop the fuel injectors from working, meaning that fuel can’t enter your engine even if you have a full tank. Similarly, if the fuel pump fails, then your Mercedes has no way of transferring fuel from the gas tank to the fuel injectors.


If the engine cranks slowly but doesn’t turn over, your Mercedes probably has a battery issue. When battery power is low or there is corrosion on the terminals, it will negatively affect your power output, and you’ll struggle to start your Mercedes.

Sensor Malfunction

Your Mercedes relies on two sensors during the starting process, the camshaft position sensor and the crankshaft position sensor. If either sensor malfunctions, the engine won’t be able to start. The same can be said for the throttle position sensor too.


If your starter motor is struggling, then your ignition system won’t be able to turn on and neither will the fuel injectors. This means no fuel and no spark to ignite it. This type of failure results in a cranking engine that makes odd noises. When this issue goes unresolved it will result in an engine that doesn’t even crank.

Security System

If your Mercedes is a newer model, then it likely has an advanced security system. The security system can prevent your ignition system from working in times of car theft, but it also can stop you from starting your car if it malfunctions.

Troubleshooting the Problem

There are some simple troubleshooting processes you can undertake to try to get to the bottom of why your Mercedes isn’t starting. First, pop the hood and check:

  • Is the battery properly mounted?
  • Are the cable clamps connected properly?
  • Is there rust or corrosion around the battery terminals?

If everything seems fine, next, try cycling your engine using the following steps:

  • Turn your key from the off position to the start position ten times.
  • Wait for a few minutes before trying to start the engine again.
  • If this doesn’t work, you can try this once more, but don’t try doing this over and over, as you can damage your Mercedes.

Finally, you can try shifting your car by pressing the brake pedal and shifting your Mercedes to neutral. Try starting the engine. If nothing happens, shift your car into park and try again. If none of these tips work, you’ll need to call for roadside assistance for a tow to a reputable service center.

Keith Cox Autobahn

At Keith Cox Autobahn of Bellingham, WA, Mercedes Starter Motor Replacementwe believe that getting your Mercedes repaired should be quick and stress-free. That’s why we only hire expert technicians who utilize state-of-the-art equipment. We will have you back on the road safely with little downtime. Call us today for an appointment to speak with one of us.

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