BMW 3 Series F30 white front view
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What to Do if Your BMW 3 Series Won’t Start? (7 Fixes)

8:30 a.m. on a Monday morning. You roll out of bed, throw on some clothes, and head to your car to go to work.

As you try to start it, you realize that the engine is quiet – too quiet.

You look at the dashboard and see it is lit up with warning lights.

Uh oh – what do you do now?

If this has ever happened to you, don’t worry – I’ve been in similar situations and picked up a few tricks along the way.

Here are seven things to do if your BMW 3 Series won’t start:

  1. Check your battery voltage
  2. Use an OBD reader to check for any fault codes
  3. Make sure your car doesn’t have a parasitic draw
  4. Try starting your car with the spare key
  5. Make sure your starter is working
  6. Check for fuel delivery issues
  7. Make sure all spark plugs are firing

In this article, we will walk you through several possible fixes for when your car won’t start.

We hope at least one of these solutions helps get your car running again!

7 Things to try if your BMW 3 Series doesn’t start

The BMW 3 Series has several pros and cons, but bad reliability isn’t necessarily one of the cons.

In fact, we found that the 3 Series generally lasts at least 250,000 miles.

Plus, the G20 BMW 3 Series is one of the brand’s most reliable models.

But like every car, the BMW 3 Series has a list of common problems.

So, if your BMW 3 series doesn’t start, you can try a few things before taking it to a mechanic.

Here is a list of seven things to check!

1. Check your battery voltage

One of the most common reasons why a BMW 3-Series won’t start is because the battery is dead.

BMW 3 Series generally require a significant battery voltage to start since they’re equipped with lots of electronics. If your battery voltage is too low, your car won’t start.

The main signs of a bad battery on your BMW 3 Series are the following when turning the key or pressing the start/stop button:

  • No or fewer lights lighting up on the dashboard
  • No radio turning on
  • No noise coming from the car

However, even when your dashboard lights or radio turn on, your battery voltage may still be too low to start the car.

That’s because it takes much more power to turn over the engine than to power these electronic systems. So, in this case, it may still be your battery that’s causing the problems!

If your battery is over three years old, it’s a good idea to have it tested to see if it needs replacing. You can usually have this done at your local auto parts store.

Measuring a car battery - Illustration

Alternatively, if you have a multimeter (you can find multiple on Amazon, like this one), you can connect it to your battery’s positive and negative terminals to test the battery yourself.

To start your BMW 3 series, your battery should ideally have a voltage of around 12.5 volts.

2. Use an OBD reader to check for any fault codes

If your BMW 3 Series doesn’t start, it may have a fault code that prevents the engine from running. (Especially if you may have tuned your BMW 3 Series.)

To identify this fault code, you can use an OBD reader. This is a device that you can plug into your car and use to read any errors your car may have.

One of the most popular OBD readers on the market comes from Carly:

Carly homepage

It’s a device you can plug into your BMW, which pairs with an app on your phone. On the app, you will see whether or not your car has any issues:

Carly OBD reader diagnostics

If you’re interested in Carly, click here for a £5 discount at checkout using the coupon code ‘5offCarly‘!

Hidden feature: Did you know you can create many useful shortcuts in the iDrive system? Take a look at this article for more BMW 3 Series tips and hidden features!

3. Make sure your car doesn’t have a parasitic draw

A parasitic draw drains electricity from your battery even when your car is off.

It’s often caused by aftermarket components, such as a radio, speaker system, headlights, or fuses.

Low-voltage battery illustration

If your BMW’s battery has just been replaced and it’s not starting, this is likely the issue! In this case, we suggest getting your car checked by a local mechanic.

4. Try starting your car with the spare key

Most BMWs are equipped with an EWS (Electronic Immobilizer System), a security feature that ensures only a key specific to that car can start it.

Sometimes, the connection between your key and your car can malfunction, a common issue seen in the EWS system.

To test if this is the cause for your BMW 3 Series, try starting your car with the spare key.

If it works, it’s a sign that your primary key lost its connection to the EWS system and may need reprogramming or replacement.

BMW car key
Source

If your BMW 3 Series has a start/stop button, it’s also possible that the battery in your key is too weak. In this case, your car doesn’t pick up the signal from your key and won’t start.

When this happens, an error message will likely be displayed on the dashboard!

One last thing you can try is to lock and unlock your car a few times and then try to start it again.

5. Make sure your starter is working

If your batter and key are fine, your starter may be bad.

The starter is responsible for turning over the engine when you turn the key.

If the starter is bad, the engine won’t be able to turn over, and the car won’t start.

A friend once shared a trick to tap the starter motor with a wrench if it’s not working; it might just be stuck.

Car starter motor

You can also check your starter at your local auto parts store or get it checked by a mechanic.

6. Check for fuel delivery issues

If your BMW 3 Series engine cranks but the car doesn’t start, then there may be issues related to fuel delivery.

Here are the three main issues related to fuel delivery:

  • You don’t have enough fuel in the car
  • Your fuel pump is faulty
  • Your fuel filter is clogged

So, the first thing to check is whether or not there’s fuel in the tank. If there isn’t, then you’ll need to add some before proceeding.

If there is fuel in the tank, then you’ll need to check whether or not there’s power getting to the fuel pump.

You can do this by disconnecting the fuel pump relay and testing it with a multimeter. If there’s no power getting to the relay, then you’ll need to replace it.

On most BMW 3 Series, the fuel pump is beneath the rear seats.

When you turn over your key, you may hear something similar to a buzzing sound from your fuel pump. If you hear this, your fuel pump is most likely working.

Another reason you might not get fuel to your engine is because of your fuel filter.

Clogged fuel filter - illustration

If you haven’t replaced your fuel filter for a long time and used low-quality gas, it may get clogged and prevent fuel from reaching your engine.

It goes without saying that when fuel doesn’t reach your engine, it won’t start!

One way to test if the fuel filter is clogged on your BMW 3 Series is to get some starter fluid and spray it into the intake.

If your car starts or sounds like it’s almost starting, you know you have a problem with fuel reaching your engine.

7. Make sure all spark plugs are firing

If there’s fuel in the tank and power getting to the fuel pump, then chances are that there’s an issue with the spark.

The first thing to check is whether all the spark plugs are firing.

A row of firing spark plugs - illustration

You can do this by removing each spark plug and testing it with a spark tester. If any plugs are not firing, you’ll need to replace them.

The next thing to check is whether or not there’s power getting to the coil pack. You can test this by disconnecting one of the coils and testing it with a multimeter

Why is my BMW clicking but not starting?

Is your BMW 3 Series clicking, or are the lights flickering when you try to start it?

If your BMW is clicking but not starting when you turn the key, it’s most likely caused by an empty or dead battery. Measure your battery with a multimeter and make sure it has a battery voltage of at least 12.5 volts.

When your battery is running low, it may have enough power to power things like your dashboard lights, but when you try to start the car, it doesn’t have enough punch to power your starter.

Because this power goes to your starter, your BMW might start clicking when you try to start it!

Note: You can find some additional causes of why a BMW might not start here!

Can a fuse cause a BMW not to start?

In rare cases, a blown fuse can cause your BMW not to start. This mainly happens when a blown fuse is linked to your starter relay or fuel pump.

So, if your BMW doesn’t start and you checked all other things on this list, you may want to check your fuse box and ensure all your fuses are still intact!

A box of fuses

Conclusion

It is always frustrating when your car doesn’t start.

However, sometimes, there is a simple thing you can do to troubleshoot the problem.

We hope that this list helps you make your BMW 3 Series start again!

If it did, let us know in the comments below.

Have a great rest of your day!

Related article: BMW 3 Series: Which Years To Avoid & To Buy? (2023 Guide)

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