Car won't start: 9 common causes

First, notice what the car does when you try to start it. That one clue narrows things down fast:

• Nothing at all, or the dashboard is dark: almost always the battery or its connections.
• Rapid clicking, or slow, weak cranking: a weak battery. See car clicks but won't start.
• One click, lights stay bright: often the starter motor.
• Engine turns over normally but never fires: fuel, the key or immobiliser, or an engine fault.

Likely causes, most common first

1. Flat battery

   Lights left on, a long time parked or lots of short trips can drain the battery. Signs: slow cranking, rapid clicking, dim lights. A jump-start or a portable jump starter usually gets you going. Then drive for 20 to 30 minutes, or charge it, so it can recover.

   Read the fix guide →

2. Worn-out battery

   Batteries usually last three to five years, less in hot climates. If you need jump-starts often, or the battery is old, swollen or smells of rotten eggs, it needs replacing. Most parts stores and garages will test it for you.

   Read the fix guide →

3. Loose or corroded battery terminals

   Vibration can loosen the clamps, and white or green crust on the terminals blocks the current. The symptoms look exactly like a flat battery. With the engine off, check the clamps are tight and clean.

4. Faulty alternator

   The alternator recharges the battery while you drive. If it fails, the battery slowly runs flat and the car will not start again. Clues: the battery warning light came on while driving, or the car starts with a jump but dies again later.

   Read the fix guide →

5. Failed starter motor or solenoid

   The starter turns the engine over. When it fails you often hear a single click, or nothing, while the lights and radio work normally. This is a garage job.

6. Key fob battery or immobiliser

   On keyless cars, a dead fob battery can mean the car does not detect the key. A flashing key or security light on the dashboard points here. Your owner's manual explains the backup method, often holding the fob right against the start button. Try your spare key too.

7. Out of fuel or a fuel delivery fault

   The engine cranks normally but will not catch. Check you have fuel: a faulty gauge can read higher than the real level. A failed fuel pump or a blown fuel pump fuse also stops fuel reaching the engine. Fuel system repairs are a garage job.

8. Not in Park, or clutch not pressed

   Many automatics only start in Park (some also in Neutral), and many manuals need the clutch pedal fully down. Move the selector firmly into Park and try again.

9. Steering lock

   On cars with a traditional key, the steering lock can jam the key so it will not turn. Turn the steering wheel gently left and right while turning the key.

What it costs to fix

Alternator replacement often costs more than a starter; get a written quote for your car, as prices vary widely by make.

DIY or garage?

How to prevent it

• Have the battery tested every year once it is three years old.
• Keep the terminals clean and tight.
• If the car sits for weeks or you only do short trips, use a battery maintenance charger.
• Replace the key fob battery as soon as the car warns you it is low.
• Never ignore the battery warning light while driving.
• Keep a portable jump starter in the car, charged.