Car Won't Start

Causes & Solutions

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Is your car not starting? This can be very nerve-wracking, especially if you need to get somewhere urgently. The most important thing here is to stay calm! Maybe it's not as bad as it seems.

In this article, we present the most common causes and possible solutions to the "car won't start" problem. The aim is to get you back on the road as quickly as possible.

Contents
  1. Remedy with diagnostic device
  2. 1) The battery is flat or defective
  3. 2) A defective alternator
  4. 3) A defective fuse
  5. 4) The starter motor is defective
  6. 5) The engine lacks fuel
  7. 6) The spark plugs or glow plugs are defective
  8. 7) Defective or clogged fuel filter
  9. 8) Other errors & causes
  10. Prevention tips to keep your car in good condition:
  11. Conclusion: Car does not start
  12. More Articles

Remedy with diagnostic device

We recommend this list of causes & solutions exactly in this order.

However, a big help in finding the problem would be a Diagnostic device. With the Reading out the fault memory you recognize the cause of the starting problem clearer and faster. A reliable and affordable diagnostic device that is easy to use but still offers many functions would be a MUCAR CS4:

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1) The battery is flat or defective

One Empty battery or a battery with low voltage is a possible culprit. In this case, the main problem is that there is no sufficient energy source to power the Operating the starter motor and start the engine.

Causes of defective or empty Car batteries are:

Power guzzler: Lights, radio or other electronic consumers drain the battery when the vehicle is switched off.
Defective alternator (generator): The battery is only discharged and no longer charged by the alternator when the engine is running.
Short distances: The starter draws a lot of current when starting the engine. If you drive a lot of short distances, the alternator may not be able to generate the consumed current back.
Short circuit in the circuit: If a short circuit has occurred somewhere, the battery may discharge completely, depending on the situation. This can even lead to a defect in the battery.
Lifetime expired: A battery does not last forever. If you have an older car, it may well be that the battery is slowly giving up the ghost.

Solution for flat or defective battery

You can check whether the battery is faulty using a Multimeters to find out. To do this, set the Multimeter * on DC voltage and measures with the two tips between the negative & positive poles. If the voltage is below 12Vyou can assume that, that the battery is empty. Then charge the battery with a Charger *and try to start the engine 1 day later. If it still does not work, the battery is faulty.

Measurement on the battery with a multimeter --> battery has 12V --> battery is not defective
Battery has over 12V -> battery intact

If you are in a hurry, of course a Jump start in this situation. However, if the battery or alternator is faulty, you can expect your car to still cannot start after switching off. In this case, you should look for a new battery and buy from a professional service provider or a vehicle parts dealer.

The cost of car batteries varies greatly. You are on the safe side if you go with approx. 250€ for a mid-range car. Here you can usually find great deals on car batteries: autobatterienbilliger.de *

Jump start if car does not start
Jump start as a temporary solution when you're in a hurry

2) A defective alternator

It can be difficult to find out whether the Problem with the battery or alternator. If the battery is flat, it may be because the alternator is no longer working and the battery is therefore not being charged. For this reason, it is important to Distinguish between symptoms.

Causes of a defect in the Alternator are:

Defective charge controller: The reasons for this are either excessive heat or excessive current load on the controller.
Carbon brushes worn: The carbon brushes of the alternator can wear out. If this is the case, the indicator light for the battery in the on-board computer normally lights up.
The V-belt is loose: If the V-belt has been running spongy for a long time, this could have led to problems with the alternator's current development.
Car does not start due to defective alternator
Alternator (also called generator or simply alternator)

Solution for defective alternator

To do this, you should use the Charge the battery and leave it for a day. If the voltage at the battery is still the same or only slightly lower after one day, you can use a Start the joyride and then switch the engine off again. If the engine then fails to start again on the next journey, the cause is Defect in the alternator. However, if the voltage is a lot lower after a day, it is due to the battery. Theoretically, you could use the Also measure the generator:

1.) Start the engine (jump start) and set the multimeter to Direct voltage (DC).
2) Hold a measuring tip to the Thick red cable of the alternator and the other to the Metal of the housing.
3) If the multimeter shows less than 13.8 Volt is the Alternator defective.
Measure alternator with multimeter
Alternator measurement: Should be over 13.8 volts

However, you should first use the Check charge controllerbefore you condemn the entire unit.

You will need a comprehensive measurement to find out whether it is the charge controller or the alternator. It is easier if you use the Diagnostic device * and the Interpret error code. Alternatively, you can simply replace the charge controller first to see if the problem persists. A new Charge controller costs around €100. However, depending on the car model, a new alternator can cost around 300€ cost.

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3) A defective fuse

One Blown fuse can also be the reason for starting problems. However, you can immediately determine whether it is due to a defective fuse. excludeif you have the You can hear the starter motor turning. If, after turning the ignition key, only a "Clack" be audible, it is also not on the fuse.

Only if If there is no audible "turning of the starter motor" and no clicking of the relay when the ignition is switched on, it could be due to a blown fuse.

Solution for defective fuse

If you try to start the engine hear nothingyou can use the operating instructions to locate the affected fuse and then replace it. change. The fuse box is located either in the Engine compartment, in the driver's footwell or on the side of the dashboard of the driver or co-driver.

On some models you will find the fuses in the trunk on the side walls.

Difference between intact fuse and blown fuse
Detect whether the fuse has blown
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4) The starter motor is defective

The Electric starter is responsible for starting the engine properly. The short-term "Rotating noise" after pressing the start button or turning the car key comes from the starter motor. The starter is usually located in the Proximity to the motor and is often more accessible on older models than on newer cars.

Common causes of damage to the Starter motor are:

Corrosion: Caused by high humidity over a long period of time or by de-icing salt on the starter motor. Driving through deep water also accelerates corrosion.
Worn brushes: Current flows through the carbon brushes. If these become worn due to repeated starting of the engine, the starter motor can break down.
Electric motor or pinion is defective: The starter motor is an electromechanical component. Electrical and mechanical damage can therefore occur inside.
Car won't start due to defective starter motor
The starter motor with electric motor and pinion

Solution for defective starter motor

To find out whether the cause of the engine not starting is the starter motor, you must contact the Listen carefully to the starting process. If you only have one "Clack" it is highly likely that only the starter solenoid has gone off.

However, the starter itself is not. If everything is in order with the battery and the wiring, the Starter motor defective or needs to be restored.

However, to save you a lot of work and nerves, we recommend that you use the Change the complete starter motor. This can be 100€ to 200€ costHowever, it is certainly worth the money. Otherwise, you can try to restore the starter yourself, which is usually not worth the effort. In the end, either the Pinion, the electric motor or the carbon brushes of the starter motor are broken.

Position starter/starter
Installed starter motor (usually near the engine)

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5) The engine lacks fuel

You may laugh now, but in most cases it's something as simple as a Lack of fuel in the engine. If your car's fuel tank is empty or even nearly empty, it needs more fuel to start the engine.

If you suspect that the problem is related to a lack of fuel, you should check the Fuel gauge and fill up with fuel immediately.

Empty tank cause of starting problems: Fuel gauge
It can happen to anyone: The tank is simply empty and the engine won't start

Further damage to the Fuel system you can exclude for the time being. If your car still won't start after the following points, you should also consider the fuel system as a possible cause.

6) The spark plugs or glow plugs are defective

With diesel, it is the Glow plugs and for the gasoline engine the Spark plugs. Roughly speaking, however, it is the same principle. In order to start the engine, the spark plugs or glow plugs must be intact.

A kaputter spark plug is often the reasonthat a car will not start. The spark plug is supplied with power by the battery. If the spark plug is defective, the fuel-air mixture cannot be ignited and the engine stops.

The most common causes that lead to a defect in the Glow plugs or spark plugs are to be managed:

Quick start in winter: If the spark plug is not preheated long enough (kept in the ignition position) in cold seasons.
Poor fuel quality
Damaged cylinder head gasket: If oil and coolant are mixed and burnt, this can cause heavy deposits on the spark plug.
Lifetime and short distances: This is mainly caused by wear. The more often you start the engine, the more the spark plugs wear out.
Car won't start due to defective spark plugs
Intact (left) and defective (right) spark plug

Solution for defective spark plug

Whether it is due to the Spark plugs (gasoline) or the glow plugs (diesel) can also be measured. Here you will find a Instructions for measuring the spark plugs under the point: Defective spark plugs/glow plugs.

However, it never hurts to use the candles easy to replace and see if the car starts afterwards. Sooner or later your car will need a spark plug replacement anyway.

7) Defective or clogged fuel filter

If the car is still unable to start, you will need to take a look at the throw under your car must. On the Driver's side in the center of the vehicle under the underbody protection you will find the Fuel filter. If the filter is clogged, not enough fuel can get through to the injectors and the car will not start.

Minimal dirt is often deposited during refueling and in the tank itself, which intercepted by the fuel filter becomes clogged. This can clog the fuel filter and cause problems when starting.

Fuel filter position
Position and appearance of the fuel filter

Solution for clogged fuel filters

As it is difficult to judge whether the fuel filter is clogged, only a change will help here. It is not difficult to change the fuel filter and it is even part of the Service routine for this. So if you have forgotten to check the fuel filter several times during maintenance, this could also be the cause of the engine not starting properly. A new fuel filter doesn't cost much either: approx. 20€ to 35€.

8) Other errors & causes

Under this point rather Rare errorsthat lead to problems with starting the engine. If your car still does not start, it is worth taking a look at the following points:

The engine is not getting any air: If the air filter is clogged or the air intake tract is blocked, the engine chokes and cannot start.
Is the key ok? However ridiculous it may sound, check your keys to make sure they are the right ones.
Cut cables: Martens or rats could have cut important cables. Try tracing the cables from the ignition lock to the starter motor.
Severed fuel lines: Is fuel perhaps dripping out of the middle section of the car?
Oil leaking? Sometimes a quick look under the car is enough to find the cause of the starting problems.

Prevention tips to keep your car in good condition:

Regular maintenance - Clean and regular maintenance is essential.
Check the liquids - Keep an eye on your vehicle's fluid levels and make sure they are topped up when necessary. Contaminated coolant or oil can lead to many problems
Use the right fuel - Filling up with a better quality diesel instead of the normal one is good for the engine.
Cleanliness - Do your best to keep the engine compartment clean.
Car does not start due to faulty maintenance
Check the engine oil and coolant regularly

Conclusion: Car does not start

Here we have listed some reasons why your car won't start and how you can solve these problems. is the easiest to fix.

Nevertheless, the best helper in such situations is a Diagnostic device. If faults such as starting problems occur, you can simply connect a diagnostic device and check the Reading DTC Codes. With the error code and the description, you can investigate the problem more precisely and save yourself unnecessary steps.

There are almost endless offers for OBD scanners on the Internet. However, it is not always the case that these diagnostic devices deliver what they promise. We therefore recommend a Affordable diagnostic device for hobby mechanicswhich we also use and are satisfied with:


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