Mercedes S-Class Wont Start? Here’s Quick Solutions to Most Common Problems

Mercedes Wont Start up

Intro

As an experienced mechanic with over two decades of hands on experience, I’ve helped plenty of people struggling when their Mercedes S-Class Won’t Start. And let’s be honest, not being able to start your car when you need to drive is incredibly annoying.

But don’t worry, you’ve come to the right place, no need to keep googling searches like “why my Mercedes won’t start“, I got you covered. My name’s Robby, a certified auto mechanic with over two decades of experience, and in this guide, I’ll walk you through the most common causes for why your S-Class can’t start. I’ll discuss all the typical culprits so you can diagnose what’s causing issues, plus what to do to fix each specific situation. Drawing on my two decades of personal experience, I’ll provide practical repair advice to get your Mercedes S-Class up and moving as quick as possible!

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Why Won’t My a Mercedes Start?

Mercedes S-Class wont start

Before we dive into the list of possible issues and solutions, it’s key to first get on the same page of the core problem. When you climb into your Mercedes S-Class and realize “it won’t start!”, there could be multiple parts causing the headaches. Perhaps the engine doesn’t turn over whatsoever, or possibly it’s turning over partially yet not igniting. Or you might hear clicking when you try to start it, but ultimately nothing happens. All these situations can indicate various mechanical issues.

Common Reasons Why Your Mercedes S-Class Won’t Start

There are numerous culprits as to why your S-Class won’t start up. Typical causes include a dead or weak battery, defective alternator, starter motor issues, fuel system problems, plus electrical or wiring issues. Every one of these concerns can present differently, needing specific methods of troubleshooting and fixing to get you back on the open road ASAP. All of which, we’ll delve into.

Symptoms of a Mercedes S-Class That Won’t Start

Recognizing these symptoms will guide you toward the underlying mechanical problem. Take for example, when you turn the key or press the start button and you hear it clicking but no ignition, it often means a problem with either fuel delivery or ignition issues.

Analysis of The Reasons Why Your Mercedes S-Class Won’t Start

The first step in remedying the no-start headache is pinpointing the specific source of the trouble. So let’s explore the most frequent explanations for the S-Class struggling to start when you turn the key.

Battery Issues in a Mercedes S-Class

car wont start but battery is good
Image Credit: MechanicAnswer.com

In the majority of cases, the most typical reason a Mercedes S-Class won’t start comes down to issues with the battery. Specifically, a weak or dead battery prevents the engine from turning over. The car’s battery delivers the required power to ignite the engine and energize all your electronics. Signs of a struggling battery include labored or difficult cranking, dim headlights, or a warning light illuminated on the dash. A battery charger can recharge a dead battery if you don’t have the help of another vehicle to jump start it, but do have an electrical socket nearby like at home.  And a portable jump starter lets you charge p the battery without another vehicle, and by the roadside without the need for an electrical socket, so you are never stuck.

Alternator Problems in a Mercedes S-Class

car wont start alternator

The Alternator keeps the battery charged by harnessing engine power while driving. A busted alternator can easily stop your Mercedes S-Class from starting since it fails to recharge the battery, depleting it fully so that one day you hop in your beloved Mercedes S-Class and it just can’t start. Signs of a faulty alternator can be an illuminated battery or alternator warning symbol on its dash, faint headlights while idling, or a grinding noise from the engine while running.

Starter Motor Failures in a Mercedes S-Class

car wont start wont turn over

The starter is crucial for turning over the engine when you go to start up your Mercedes. In the event of starter problems, the engine may fail to crank, preventing your S-Class from starting. Listen out for clicking sounds when you turn the key or grinding while trying to start, possibly meaning starter problems.

Fuel System Issues in a Mercedes S-Class

car wont start fuel filter

We’re not talking about running out of gas like a silly goose. Rather, it’s problems in the fuel system itself that could leave your S-Class unable to drive. Your car uses gas uses gas to mix with air and runs the engine. So problems here like a clogged fuel filter or failing fuel pump relay can result in the engine is unable to get the fuel it requires for ignition. Fuel injectors can also get clogged over time, so try a fuel injector cleaner like Red Line to clear any blockages and improve starting.

Electrical System or Wiring Problems in a Mercedes S-Class

car wont start electrical issue
Image Credit: MechanicAnswer.com

Ok, well yes that image is a joke, but I want to emphasize modern cars now rely heavily on electronics, opening up what can go wrong. Even in older cars, the usual suspects include blown fuses, ignition problems, broken ignition switches, or non-working sensors. Electrical issues and electronics like these may prevent your vehicle from starting. Be on the lookout for your car only starting sometimes, warning lights, or failure to crank as indicators pointing to an underlying electrical issue. Pinpointing and fixing these often needs a knowledgeable mechanic near you.

Solutions: Let’s Get Your Mercedes S-Class Starting Again!

If you think you might know what the issue may be, it’s time to figure out the reason behind your car’s inability to start up, and then the logical next move is to attempt to repair the issue. Here’s advice for the frequent problems we’ve discussed up to this point:

How to Identify and Fix Battery Issues in a Mercedes S-Class

car not starting but battery is fine

If you believe a battery issue is to blame for your Mercedes’s difficulty turning on, first inspect the battery terminals Make sure they are corrosion-free, secure, and correctly connected. If the terminals are in fact corroded, try scrubbing them with a sodium bicarbonate(baking soda) and water solution.

Once you have checked the battery terminals, you can check to see if the battery is just out of charge, or worse, it’s old and weak, or dead and needs to be replaced. For this, you can charge the battery in a few different ways:

If the battery charges fully and performs as expected, the issue may be resolved. However, if the battery has aged or lacks capacity, replacing it will be necessary. Otherwise, even sufficiently charging it to start your S-Class may only provide temporary relief before it likely runs out of power again soon. Using a multimeter or OB2 scanner to evaluate the battery’s condition can determine if it’s worth preserving or requires swapping out. Suitable replacement batteries for your specific Mercedes can be found on Amazon here by entering your vehicle details to filter for the right fit and choosing a highly-rated seller.

Robby Recommends:

Portable Car Battery Jump Starter Charger - NOCO Boost Plus GB40

At Home Battery Charger - YONHAN - Fully Automatic

Jumper Cables by Energizer for Car Battery - Heavy Duty

NOCO Boost Plus GB40 1000A UltraSafe Car Battery Jump Starter

YONHAN Battery Charger Fully-Automatic

Energizer Jumper Cables for Car Battery, Heavy Duty

If charging your S-Class’s battery fails to solve ongoing issues like frequent draining and recharging even after installing a new battery, an underlying problem likely causes the excessive drain. Professional diagnostic services would then be needed to inspect and identify the root cause. You can also consult a mechanic online through us or obtain an instant quote from a mobile mechanic.

How to Identify and Fix Alternator Problems in a Mercedes S-Class

Car wont start replace alternator needed

If you think the alternator is the reason your vehicle won’t start, a test can confirm. If you can temporarily get the auto running (you may need a jump start), with the engine on, detach the positive battery terminal. It’s probably the alternator if the engine dies soon after disconnecting the positive lead. However, be cautious this test can be risky and mess up sensitive electronics in your ride, so seeking advice from a qualified mechanic in your area or online is best before trying it.

If you figure out that the alternator is the problem, it’s a case of having it replaced. I recommend consulting an online or local mechanic as they will advise you on how difficult the repair is for your specific model, and you can work out if you want to try it yourself, or with the advice of an online mechanic

If you do want to try it yourself or take it to a local garage, you can often buy the replacement parts yourself cheaper than at the garage, but you need to know what to get for your model of Mercedes S-Class. You find all the information you need about your specific vehicle by searching online for something like “run Mercedes vin for free“, which is a purchasable report, that will give the specs for your vehicle and which parts are compatible, and then you can go get the alternator parts you need. However, an easier option is, Amazon probably has the alternator you need online, at a cheaper price, and their site easily shows which ones will go in your specific car model. Check the Amazon alternator page here

How to Identify and Fix Starter Motor Problems in a Mercedes S-Class

starter motor issues in a ford

If you question if the starter motor is the source of your S-Class failing to ignite, listen for a clicking sound when you turn the ignition key. If present, but the engine does not turn over, the starter motor likely requires replaced. You can take it to a local garage and have them repair it, or repair it yourself with the help and advice from an online mechanic guiding you. 

If you need it, one of the cheapest and easiest places to get a new starter motor, for your exact vehicle model is on the Amazon here.

How to Identify and Solve Fuel System Problems in a Mercedes S-Class

clogged fuel filter car wont start

If you suspect a fuel system issue might be causing the no-start, listen closely for the fuel pump noise when you flip the key to “on” before trying to turn over the car. The pump should emit a faint humming for a few seconds. If such a noise is not heard, the fuel pump could be defective. Problematic starting, stalling, or lagging acceleration may also stem from a clogged fuel filter. Filter and pump issues usually require a skilled mechanic to diagnose and fix them properly, often using fuel pressure testing and precise diagnostic equipment. Later in this article, I detail the best ways to get help from a local Mercedes mechanic near you. 

How to Fix Electrical or Wiring Issues in a Mercedes S-Class

fuses to check when car wont start

If you think it’s an wiring issue, first inspect the fuses for the ignition system, and replace any that have blown. If your S-Class starts after this, it was an effective, inexpensive repair! However, if it still won’t start, even sometimes, the ignition switch itself could be the cause of the issue. Warning lights on the dashboard could additionally mean a faulty sensor. These can be intricate problems needing a professional mechanic to diagnose and properly repair (see below advice on local mechanics).

How to Prevent Starting Issues in a Mercedes S-Class

As grandad would say: “An ounce of prevention is worth a pound of cure”. Here’s how to avoid future issues starting your S-Class:

Regular Maintenance of Your Mercedes S-Class

Regular maintenance on car to prevent starting issues

Regular maintenance is essential to avoiding issues, including oil changes, battery checks, cleaning terminals, replacing the fuel filter as needed, and having a mechanic inspect the vehicle regularly. If confused about maintenance for your model, consult a mechanic locally or online for guidance.

Drive Your S-Class Frequently

drive regular to avoid car troubles

If your Mercedes S-Class happens to sit motionless in the garage or driveway for extended times without being driven, the battery can decrease as it is not being charged up by the engine running, through the alternator. Try your best to use your Mercedes S-Class regularly to keep a charged battery. If you remember you have not driven your car in a while, take it for a brief spin around town to ensure there is still a charge left.

Note: Letting the battery completely run out of charge is also bad for its longevity, so try to avoid that.

Take Notice Of Warning Signs

Check Engine Control Light on a Vehicle Dashboard

If you notice any abnormal things like unusual noises, changes in driving and performance, or warning lights lit up on the dashboard, do not ignore them. These are often early signs of an issue that should be addressed ASAP before they escalate into larger problems later on. Consult with a mechanic locally or online about these problems and get advice on if they require attention.

When to Ask a Mercedes Mechanic Online

If you have limited time available, or despite putting in real effort on your own, you still can’t get your car to start, consider consulting a Mercedes mechanic online. It delivers expert guidance in just minutes from the comfort of your living room, and is far less expensive than a tow and diagnosis at the local garage.

Benefits of an Online Mercedes Mechanic

Happy mechanic repairing car looking at camera

By detailing what you’ve already tried and sharing specifics on the no-start issue, online mechanics can then offer a custom action plan to help get your car started again. With so many Mercedes mechanics available they can help fix nearly any problem, it doesn’t if matter it’s your S-Class that’s having issues or a Mercedes R-Class won’t start, the online mechanics can help sort anything in no time. And with many household budgets tighter these days, an online mechanic provides instant affordable help when you need it most, 24/7.

You can explain the issues you’re having, ask Mercedes mechanics unlimited questions, and even submit pics and videos so you can demonstrate to the expert what you mean. You can chat with them via online chat or voice chat, whichever you prefer. The Mercedes mechanic will ID the problem, recommend the top solution for your particular situation, and even guide you on simple maintenance step-by-step.

Whether you want an expert second opinion or are simply short on time, online repairs assistance is there when you need it. Give it a try – you may be surprised just how easy and stress-free it is.

So feel free to try out our chat with a Mercedes mechanic for free online service and see for yourself!

When and How to Get a Local Mercedes Mechanics Help

automobile mobile mechanic

When your Mercedes S-Class won’t start, and you are unable to repair it yourself, thinking about how to get your vehicle to the garage can be a nightmare. There are options like roadside services, that come to you and can provide simple fixes to get your car moving enough again, so you can get it to a mechanic garage for proper repairs. You can also use a towing service, but these can be costly, easily into the hundreds of dollars. A much better option is the use of a mobile mechanic, who will come to you at your home, place of work, or by the roadside, and carry out repairs there and then for you, so you can get your S-Class started again ASAP.

So if you think a mobile mechanic is the best solution for you, instead of searching on Google something like  “mobile car diagnostic services near me“, the best in the USA that also covers most towns is YourMechanicI have personally recommended them to countless people across the country and they always have a great experience.

Reasons I recommend them:

  • They use experienced ASE-certified mechanics
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If you would like to know more, the process to use them is this.

  1. Visit their official website here: YourMechanic
  2. Get an instant free quote for what you need
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Conclusion

In short, when your Mercedes S-Class doesn’t turn over, it can be a major inconvenience. However, grasping what might be triggering the problems, being able to diagnose them, and knowing what steps are required in each case, and where to find help if necessary, will be a huge help. Remember that regular maintenance is vital to avoiding most vehicle issues.

Frequently Asked Questions (FAQs) When a Mercedes S-Class Won’t Start

Mercedes S-Class won’t start but lights come on?

If your Mercedes S-Class‘s lights turn on but it still won’t start, the issue may not be related to the battery. More than likely there is a problem with the starter motor. Check to see if you hear any clicking sounds when trying to turn the key. If so, the starter motor is attempting to activate but failing. Get a mechanic examine the starter motor – it may need to be repaired or replaced.

Mercedes S-Class won’t start but has power?

When your Mercedes S-Class has power (lights, radio etc work) but does not start up, there may be a fuel delivery problem. Issues like a faulty fuel pump relay could prevent fuel getting to the engine. Without enough fuel, combustion can’t happen and the engine won’t start. Listen near the back seat when turning the key – you should hear the fuel pump prime for a few seconds. If not, get a mechanic check the fuel system.

Mercedes S-Class won’t start but battery is fine?

If your Mercedes S-Class‘s battery checks out OK and is fully charged, but the car still refuses to start, the underlying cause is likely electrical. Possible issues include a bad ignition switch, broken sensor, or wiring problems. As electrical issues can be tricky, diagnosis by a professional mechanic is best. They can correctly pinpoint the specific electrical fault and have it repaired.

Mercedes S-Class won’t start just clicking?

When you turn the key and just hear clicking but the engine fails to turn over, the most common cause is a faulty starter motor. The click comes from the starter solenoid attempting to activate the starter motor, but the motor itself fails to spin up the engine. As the starter motor needs physical fixing or swapping out, consult with a reliable mechanic to get your Mercedes S-Class running again.

What if my Mercedes S-Class won’t start up?

First things first, take a deep breath and try to stay calm. Look for any odd noises, flashing lights, or changes in how it runs that could point to the issue. Most likely the culprit is one of the common problems we will talk about here. If you still can’t locate the exact issue, you’ll have to ask for help from a trusted Mercedes mechanic locally or online.

How do I know if my Mercedes S-Class won’t start because of the battery?

Signs that your Mercedes’s battery is the issue are, a slow cranking engine, dim front lights, and battery alerts lighting up on the dash. You can also make sure the battery terminals are clean, corrosion-free, and tightly fastened. If your battery is older it’s probably best to just replace it completely.

How to prevent my Mercedes S-Class from failing to start in the future?

To prevent this frustration from repeating, scheduled servicing is vital. This includes oil changes, testing the battery and scrubbing its terminals, changing out the fuel filter when required, and getting your Mercedes S-Class inspected by a mechanic frequently. Additionally, remember to drive the car often so the battery stays charged.

Can I consult an online mechanic if my Mercedes S-Class fails to start up?

Yes, you can. An online mechanic service like ours can offer instant skilled Mercedes mechanic help and advice, without you having to leave your house. This is especially beneficial if your Mercedes S-Class is unable to start and is stuck in the parking area,.

How can websites like MechanicAnswer.com lend a hand if my Mercedes S-Class won’t turn on?

We pair you with qualified Mercedes specialists who can offer proposals tailored to your individual predicament. You can brief them about your auto issues, ask unlimited questions as needed, upload images and videos so you can show in detail the problem. The mechanic will be capable to aid, identify the problem, and recommend the ideal remedy and talk you through it.

Interesting Mercedes S-Class Facts

Did you know that the Mercedes S-Class has a feature called “Energizing Comfort Control” that uses ambient lighting, music, seat massage, and even fragrance to create a relaxing and rejuvenating atmosphere inside the car? It’s like having your own personal spa on wheels! And get this – the S-Class also has a feature called “Magic Body Control” that uses a camera to scan the road ahead and adjust the suspension to smooth out bumps and potholes before you even hit them. It’s like the car has its own psychic powers! Plus, with a top speed of 130 mph and a 0-60 time of just 4.4 seconds, the S-Class is not only luxurious, but also incredibly fast and powerful. No wonder it’s the ultimate dream car for so many people!

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  1. Chat with an Online Mechanic to get instant, unlimited help and advice for 1 full week, for just $5.
  2. Get in-person help from a Mobile Mechanic Near You. They will come to you and fix your vehicle at a time that suits you. If there are none near you, you will be redirected to the online mechanic.

Which Mechanic Suits You?

  1. Chat with an Online Mechanic to get instant, unlimited help and advice for 1 full week, for just £5.
  2. Get help from a Mobile Mechanic. We  recommend Fixter. They will come to you and fix your vehicle at a time that suits you. Instant free quote online below. We recommend the online mechanic first, as it’s cheaper for you, and you may not need an in-person mechanic.

Which Mechanic Suits You?

  1. Chat with an Online Mechanic to get instant, unlimited help and advice for 1 full week, for just $5.
  2. Get in-person help from a Mobile Mechanic. We recommend YourMechanic. They will come to you and fix your vehicle at a time that suits you. Instant free quote online below. We recommend the online mechanic first, as it’s cheaper, and you may not need an in-person mechanic.

Choose Your Mechanic

1. Chat with A.I. Mechanic (Robot Robby)
  • Free 7-day trial
  • A.I. Mechanic that is trained by our human mechanic writers. As helpful as a human mechanic for expert advice, troubleshooting, and repair guidance.
2. Chat with a Human Mechanic Online
  • Join for just $5, and $39/month. Cancel anytime
  • Real human ASE-certified mechanics available 24/7

Which Mechanic Suits You?

  1. Chat with an Online Mechanic to get instant, unlimited help and advice for 1 full week, for just $5.
  2. Get in-person help from a Mobile Mechanic Near You. They will come to you and fix your vehicle at a time that suits you. If there are none near you, you will be redirected to the online mechanic.

Which Mechanic Suits You?

  1. Chat with an Online Mechanic to get instant, unlimited help and advice for 1 full week, for just £5.
  2. Get help from a Mobile Mechanic. We  recommend Fixter. They will come to you and fix your vehicle at a time that suits you. Instant free quote online below. We recommend the online mechanic first, as it’s cheaper for you, and you may not need an in-person mechanic.

Which Mechanic Suits You?

  1. Chat with an Online Mechanic to get instant, unlimited help and advice for 1 full week, for just $5.
  2. Get in-person help from a Mobile Mechanic. We recommend YourMechanic. They will come to you and fix your vehicle at a time that suits you. Instant free quote online below. We recommend the online mechanic first, as it’s cheaper, and you may not need an in-person mechanic.

Where Can I Find My VIN?

Your vehicle’s unique Vehicle Identification Number (VIN) can be found on the title document, the vehicle registration, and the insurance policy. It is a series letters and numbers like this as example: WAUGC0896JA235262. The VIN can also be located on the following locations on the vehicle itself:

how to find VIN on vehicle