The Checklist: All Possible Reasons Why Your Mercedes Won’t Start

Let’s be honest, there’s not many things that are as frustrating as trying to start your vehicle, only to discover there’s a problem and it won’t start.

Even when you own a trusted and respected brand like Mercedes-Benz, there will be times when mechanical or technical issues prevent your car from starting.

If you have your car checked and serviced regularly at somewhere like Northside service center, for instance, it will help reduce the prospect of something going wrong. However, even with regular servicing and health checks, with advanced technology and complex engineering in modern vehicles, there is always the prospect of something unexpected preventing you from starting your journey.

If you can gain an understanding of some of the reasons behind a non-starting car it can make diagnosing the problem more manageable. Let’s walk you through some of the possible reasons why your Mercedes won’t start, focusing on key areas such as electrical issues, fuel system problems, and mechanical failures.

Could it be battery issues?

The most common reason a car won’t start is a dead or weak battery. If your Mercedes makes a clicking sound or you don’t hear anything when you turn the key, this is a likely cause.

Classic signs of a battery problem are things like your dashboard lights are dim, and electrical components such as your radio and windows don’t work. You might also hear a clicking sound when trying to start, which is a common symptom of a dead or weak battery.

Try to jumpstart your car using jumper cables or a portable battery. If it starts, drive around to recharge the battery or consider replacing it if the problem persists.

Another thing to check would be whether you have loose or corroded battery terminals.

Even with a charged battery, lose or corroded terminals can prevent sufficient power from reaching the starter.

Is there a problem with your starter motor?

The starter motor is responsible for turning the engine over. If it fails, the engine won’t crank. This could be the reason your Mercedes won’t start if you hear a loud clicking sound or nothing happens when turning the key.

If the starter motor is faulty, it will need to be replaced by a service center..

The other potential cause in this area could be bad starter solenoid. The starter solenoid is a small component attached to the starter that sends an electric signal from the battery to the starter motor. A bad solenoid can prevent your car from starting.

Fuel system issues to check

It might be blindingly obvious, but an empty gas tank can easily be overlooked, especially if the fuel gauge malfunctions.

Check to see if the engine cranks but does not start and see if the fuel gauge shows empty.

A more complex problem could be a fuel pump failure. If this fails, the engine will not receive the fuel it needs to start.

Check to see if the engine cranks but won’t start, or you get no sound from the fuel pump when turning the key. If you do have a faulty fuel pump, it needs to be replaced by a service center.

The other potential cause of non-starting could be a clogged fuel filter. Over time, this filter can become clogged, preventing fuel from reaching the engine.

If you have difficulty starting your car, the engine keeps stalling, or you have a noticeable lack of power, get it checked to see if your fuel filter needs replacing.

Could you be suffering from ignition system problems?

The most common fault in this area is faulty spark plugs. These plugs ignite the air-fuel mixture in the engine’s cylinders. Worn-out spark plugs can prevent the engine from starting.

A sign that this could be the problem would be when your engine cranks but does not start. You could also suffer from a misfiring engine, or rough idling.

Get your spark plugs replaced to rectify the problem, especially if they are old or damaged.

Electrical and sensor failures are a regular source of starting problems

The first thing to check is whether you might have a faulty key fob or ignition switch.

In modern Mercedes-Benz models, the key fob and ignition switch play an important role in starting the car. A faulty key fob or ignition switch can easily prevent your car from recognizing the key.

Try replacing the battery in the key fob or have the key reprogrammed.

Alternatively, the source of the problem could be a failing alternator.

The alternator charges the battery while the car is running. If it fails, the battery will eventually drain. This will prevent your car from starting.

If you see the battery warning light illuminated on the dashboard, you might need a mechanic to replace your alternator.

Another potential cause could be blown fuses or relays. Blown fuses or malfunctioning relays can cut off power to essential components like the fuel pump, starter, or ignition system.

If your car won’t start, and you have no dashboard lights,  check the fuse box for blown fuses and replace them.

Is there a fault with your crankshaft position sensor

Modern Mercedes models are bristling with amazing technology, however that also means they rely on all sorts of sensors and gadgets to keep everything working. 

A good example of this would be the crankshaft position sensor monitor. It checks the position of the crankshaft and relays this information to the engine control unit (ECU). If this sensor fails, it can prevent the engine from starting.

Engine and mechanical issues

Sometimes, the basic mechanics of your engine can fail, despite all the technology onboard to monitor it.

A good example of this would be if you suffer a timing belt or chain failure. The timing belt, or chain, synchronizes the movement of the engine’s valves and pistons. If it breaks, the engine won’t start, and significant engine damage can easily occur.

A broken timing belt requires immediate repair and can be costly to fix.

Your starting problems could be related to security system issues

Modern Mercedes-Benz vehicles come with an immobilizer system that prevents the engine from starting without the correct key. If the immobilizer system malfunctions, the car simply won’t start.

If the security light on the dashboard stays on, have the immobilizer system checked by a service center.

It is also worth noting that in some Mercedes models, the steering wheel locks as part of the anti-theft system. If the steering wheel is locked, the car may not start.

If this happens, try turning the wheel back and forth while turning the key or pushing the start button.

As with all makes and models, if your Mercedes-Benz won’t start,  it can be as a result of a wide variety of issues, ranging from simple battery problems to complex engine failures. 

It is often a smart move to get professional assistance from a certified mechanic with Mercedes-Benz experience. As a preventative measure, keeping up with regular maintenance and watching for early warning signs can prevent many of these issues from developing in the first place.