When your car won't start, the most common culprit is a weak or dead battery, often indicated by a clicking sound when you turn the key. The first step is to diagnose the symptoms. A silent car or just a click usually points to a battery or starter motor issue. If the engine cranks but doesn't fire up, it's likely a fuel or ignition problem, like a bad fuel pump or faulty spark plugs.
Start with the simplest checks. Ensure the car is in "Park" or, for a manual transmission, that the clutch is fully depressed. Check for a dead key fob battery by using the physical key if available. Then, inspect the battery terminals for white, powdery corrosion and ensure they are tight.
If you suspect the battery, jump-starting the car is the fastest way to get moving. You'll need jumper cables and another vehicle. Connect positive to positive, then negative to the dead battery's positive and the other negative to an unpainted metal surface on the dead car's engine block. Start the working car, then attempt to start yours. If successful, drive for at least 20 minutes to recharge the battery.
If jump-starting fails or the problem recurs, the issue may be deeper. A parasitic drain (something drawing power when the car is off), a failing alternator that isn't charging the battery, or a bad starter motor are common causes. For a cranking engine that won't start, listen for the fuel pump's faint hum when you turn the key to "on." No sound could mean a dead fuel pump.
| Symptom | Possible Cause | Quick Check or Data Point |
|---|
| Single click, no crank | Dead Battery, Bad Starter | Battery voltage below 12.4V is weak; below 11.8V may not start. |
| Rapid clicking sound | Weak Battery, Loose Connections | The starter solenoid is engaging but lacks power. |
| Engine cranks normally | Fuel System (pump, filter), Ignition | A 2023 AAA study found fuel issues account for ~10% of no-starts. |
| No sound, no lights | Completely dead battery, Bad alternator | Alternators typically last 80,000-150,000 miles. |
| Car shakes but won't start | Ignition issues (spark plugs) | Modern spark plugs last 60,000-100,000 miles. |
If you're not comfortable with these steps, calling for a roadside assistance service is the safest and most reliable option. They can test your battery and alternator on the spot.
