Common Reasons Your Mercedes Won’t Start

If your Mercedes won’t start up properly, here are a few steps you can try at home for troubleshooting purposes. Check the battery for low charge or evidence of corrosion around its terminals; these could both be contributing factors.

Step two of this process should involve inspecting for an ignition system issue. A malfunctioning ignition switch can prevent your driver authorization system (DAS) from authenticating your keys, and prevent your Mercedes from starting.


If the key has been placed into the ignition (or you have pressed the push-button starter), but nothing happens, it could be because your Mercedes lacks fuel to start. Your Mercedes’ fuel pump, which delivers gas directly into its internal combustion engine, may have become clogged with buildup over time and prevent starting. Even though your lights and other electrical systems still work, this might prevent starting.

If this is the case for you, remove and inspect both battery terminals to check for corrosion. Also ensure all fuses have not blown – replace those found with new ones if applicable. Finally, ensure your battery has an appropriate charge either by using a hydrometer or taking it into a Mercedes repair shop for testing.

Another cause of Mercedes not starting up can be that its engine doesn’t get enough spark. This could happen if spark plugs wear down over time or develop holes, though this can be avoided by regularly replacing spark plugs in your vehicle.

Starter Motor

Mercedes vehicles are known for being reliable and luxurious; however, like any car they can still experience issues. One of the main causes for Mercedes not starting is due to a problem with its starter motor; this component connects directly with turning over its crankshaft so as to allow your engine to start up properly and run.

Starter motors are usually powered by both a battery and solenoid. When you turn on the ignition key, power flows from this combination directly to spark plugs and a magnetic switch attached directly to the starter motor – sending high amperage power directly into it and spinning the crankshaft to start your engine.

As soon as you turn on the key for your Mercedes’ ignition, a clicking sound should accompanying the fuel pump activation and starter motor spinning up. This indicates that both components are functioning appropriately; any problems could potentially lie elsewhere within either its fuel or ignition systems.

If your starter motor is malfunctioning, check the fuse and relays in your starter circuit, ignition system, EIS system or fuel pump. If one of them has burned out completely, replace it with one with comparable amperage which you can test using a multimeter.


The alternator is essential in keeping your battery charged, spinning to generate electricity that your car uses to start and power accessories. If your alternator stops functioning, however, this could result in starting issues; dimmed headlights or issues with other electrical components could indicate your alternator has stopped charging properly – jumper cables may help determine whether its fault lies elsewhere; visual inspection can also provide insight.

Check for corrosion on the battery terminals as this is often an issue with older batteries. If they have become corroded, clean and tighten as soon as possible; otherwise if the Mercedes won’t start it may be time for an upgrade in power.

Any number of problems could prevent a Mercedes from starting, including issues with its Battery Management System and Electric Drive Unit. A professional scanner like the YOUCANIC Full System Scanner should be attached to your Mercedes in order to diagnose its cause more economically than replacing it! Contact a certified technician for this diagnostic.

Fuel Pump

If your Mercedes fails to start or only starts with weak and stuttering power, the issue could lie with its fuel pump. Over time, fuel pumps may become clogged with residue and buildup clogging the flow of fuel and not allow your Mercedes to function normally; having your fuel system and pump inspected regularly can prevent this issue from developing and ensure that your Mercedes remains in top shape.

If it isn’t the fuel pump at fault, a fuse or relay issue could be keeping your Mercedes from starting. For instance, it could be that one of its starter circuit, ignition, EIS (Driver Authorization System), or EIS (Driver Authorization System) fuses has blown. If this appears to be the case for you, replace it with one of similar amperage to ensure the issue won’t recur.

Your Mercedes may be having issues starting due to a low battery. A multimeter can help you check how much voltage the battery is providing; additionally, inspect battery terminals for corrosion; if found, use baking soda and water solution for cleaning purposes; also consider charging your Mercedes battery to see if that helps.

Juan Gibson

Juan is an automotive engineer and an avid car enthusiast. He has over 15 years of experience in the car industry. In my free time, I write blog posts about cars, models and etc.

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button