7 Reasons Why Your Car Won’t Start & What To Do Next

We’ve all been there. You turn the key or press the start button, and nothing happens. No sound, no lights - just silence. It’s one of the most frustrating experiences for any driver, especially when you’re in a hurry or parked somewhere inconvenient. 

But don’t panic; a lot of the time when a car won’t start, it’s caused by something simple. From a flat battery to a faulty starter motor, there are a few common culprits that can stop your car from firing up. 

In this guide, we’ll walk you through seven of the most common reasons your car won’t start, how to spot the signs, and what to do next.

1. Flat or faulty battery

A flat or failing car battery is the number one reason a vehicle won’t start. Batteries naturally lose charge over time, especially if your car isn’t driven often or you’ve left lights or electronics running.

Common signs to check for:

• There is a clicking sound when you try to start the car. 
• Dim dashboard lights or none at all. 
• The engine cranks slowly or not at all. 

If your car battery is more than three years old, it might be reaching the end of its life. Cold weather, short trips, or corrosion around the terminals can also speed up the decline. 

What to do: 

Try jump-starting the car using jump leads or a booster pack. If that doesn’t work, your battery may need replacing. Kwik Fit offers free battery health checks at centres across the UK, where our technicians can check the condition of your car battery, including your battery starting and charging systems, using the latest Bosch testing equipment. 

Tip: Avoid draining your battery unnecessarily by unplugging devices and switching off interior lights before leaving the car.

2. Faulty starter motor

If your battery is fine but you hear a clicking noise (or nothing at all) when you turn the key, the starter motor could be the issue. 

The starter motor’s job is to get the engine turning, and if it fails, your car simply won’t start. This can happen as a result of age, electrical faults, or damage to the solenoid. 

What to do: 

A starter motor issue will usually need professional repair or replacement. If you’ve ruled out a flat battery, it’s best to have the vehicle checked at your nearest Kwik Fit centre for a diagnostic check.

3. Ignition switch or key fob problems

Modern cars often use keyless start systems or immobilisers, which can introduce their own challenges. If the battery in your key fob is flat, your car might not detect the key signal, even if everything else is working.

Common signs:

• The lights and electrics work, but the engine doesn’t turn. 
• The key warning light flashes on the dashboard. 
• The car doesn’t respond when pressing the start button. 

What to do: 

Try using a spare key or replace the key fob battery (they’re usually inexpensive and easy to fit). If the issue persists, it could be the ignition switch or immobiliser itself, which will require diagnostic testing.

4. Fuel supply problems

It might sound obvious, but sometimes the simplest explanation could be the most obvious one: no fuel. 

That said, issues with the fuel system can also stop your engine from starting, even if the tank isn’t empty. A blocked fuel filter, failing fuel pump, or contaminated fuel can prevent the engine from getting the fuel it needs. 

What to do: 

• Check your fuel gauge first (we’ve all been caught out before). 
• Turn the key halfway and listen for a faint whirring sound; that’s the fuel pump priming. If you don’t hear it, there could be a fault. 
• These issues should always be checked by a qualified technician, and it’s best to get expert help to be sure.

5. Immobiliser or security system fault

If your car’s immobiliser system is faulty, it might stop the engine from starting even though everything else seems fine. 

Immobilisers are designed to prevent theft by cutting power to the ignition or fuel system when an unauthorised key is used. However, a technical glitch can sometimes stop your car from recognising the correct key too. 

Common signs:

• A flashing key or padlock symbol on the dashboard. 
• The engine doesn’t crank at all. 
• The key turns, but nothing happens. 

What to do: 

Try locking and unlocking the car again, or use a spare key if you have one. If the problem continues, it’s best to seek professional support from a reputable garage for advice or a diagnostic check.

6. Faulty alternator

Even if your battery is brand new, a faulty alternator can quickly drain it and stop your car from starting. 

The alternator's job is to recharge your battery while the engine runs. If it fails, the battery will lose charge until there’s not enough power left to start the car.

Common signs:

• The battery warning light is glowing on the dashboard. 
• Headlights dimming or flickering. 
• Burning smell from under the bonnet. 

What to do: 

If you’ve recently replaced your battery but the car still won’t start, it could be the alternator. Kwik Fit technicians can confirm the cause of the issue at your nearest Kwik Fit centre.

7. Cold weather issues

In winter, freezing temperatures can be tough on car batteries. Cold weather thickens engine oil, making it harder for the engine to turn, and reduces the battery’s ability to deliver power. 

What to do: 

• Try switching off heaters, lights, and the radio before starting. This reduces strain on the battery. 
• Consider parking your car in a garage or sheltered spot overnight. 
• If your battery struggles regularly in cold weather, have it tested as it may be losing capacity. 

For peace of mind during the colder months, you can book a service at Kwik Fit to ensure your battery, tyres, and fluids are in top condition.

Keeping your car running reliably

A car that won’t start can be frustrating, but in most cases, it’s something that can be prevented with regular care and maintenance. Keeping your vehicle in good condition, from the battery and starter motor to your filters and fluids, helps avoid the kind of wear and tear that leads to non-start issues. 

At Kwik Fit, we’re here to help keep your car in its best condition. With over 600 Kwik Fit centres across the UK, you’ll be sure to have a local spot near you. You can trust Kwik Fit to keep your car reliable, road-ready, and safe, no matter the season.