Simple Checks (Do these first):
* Battery: This is the most common cause. Check the battery terminals for corrosion (clean them with a wire brush if needed). Have the battery tested at an auto parts store – a weak or failing battery can intermittently start a car.
* Battery Cables: Inspect the battery cables for damage, looseness, or corrosion. Loose or corroded connections can prevent sufficient current flow.
* Starter: A failing starter motor can intermittently crank the engine. You'll likely hear a clicking sound when you try to start it if the starter is the problem.
* Alternator: While the alternator charges the battery, a failing alternator might not be charging properly, leading to a low battery and starting problems. Have this tested as well.
* Ignition Switch: A faulty ignition switch can prevent the electrical current from reaching the starter.
* Fuel: Does the car even try to start (crank)? If not, a fuel issue is a possibility. Check the fuel gauge. If it's low, add gas. If the gauge reads fine, there may be a fuel pump, fuel filter, or fuel delivery problem.
More Complex Issues (Require more investigation or professional diagnosis):
* Security System: An issue with the car's security system (passive anti-theft system, PATS) can prevent the car from starting.
* Sensors: Various sensors (crankshaft position sensor, camshaft position sensor, etc.) are crucial for the engine to start. A faulty sensor can prevent the engine from starting reliably.
* Wiring: Damaged or corroded wiring in the starting circuit can lead to intermittent starting issues.
* Ignition Coil: This delivers the spark to the engine; a failing coil can cause starting problems.
* Fuel Pump Relay: This controls the fuel pump. A faulty relay will prevent fuel from reaching the engine.
* Computer Problems (PCM): The Powertrain Control Module (PCM) is the car's computer. A faulty PCM can cause a range of problems, including intermittent starting.
Troubleshooting Steps:
1. Listen carefully: What sounds do you hear when you try to start the car? Clicking? Nothing? Cranking slowly? This can give clues to the problem.
2. Check the obvious: Battery, cables, fuel level.
3. Have it tested: Take your car to an auto parts store to have the battery and alternator tested.
4. Professional Diagnosis: If you can't identify the problem yourself, take it to a mechanic for a proper diagnosis.
Don't attempt complex repairs unless you have experience working on cars. Improper repairs can lead to further damage. A qualified mechanic can properly diagnose and repair the issue.
