Electrical System:
* Crankshaft Position Sensor (CKP): This sensor tells the computer the engine's rotational speed and position. A failing CKP will prevent the engine from starting or cause it to die suddenly. This is a very common cause of this type of problem.
* Cam Position Sensor (CMP): Similar to the CKP, but monitors the camshaft. A failure can cause similar symptoms.
* Ignition Coil(s) or Ignition Module: These components deliver the high voltage spark to ignite the fuel-air mixture. A faulty coil can cause misfires or complete engine failure. The ignition module controls the coils, and a failure there can disable multiple cylinders or the whole engine.
* Distributor (if equipped): Older vehicles might have a distributor, and problems inside (rotor, cap, etc.) can cause intermittent or complete failure.
* Alternator: While it doesn't directly stop the engine, a failing alternator can suddenly stop charging the battery. Once the battery drains, the engine dies. This is more likely to happen if the car has been running for a while.
* Battery Cables/Connections: Corroded or loose battery terminals can cause intermittent power loss.
* Ignition Switch: A faulty ignition switch can fail to provide power to the system, killing the engine.
Fuel System:
* Fuel Pump: A failing fuel pump can suddenly stop delivering fuel to the engine. This is less likely to cause the engine to die suddenly and restart immediately. More likely it will be hard to restart.
* Fuel Filter: A severely clogged fuel filter can restrict fuel flow, but this usually leads to performance issues before complete failure.
* Fuel Pressure Regulator: If this fails, it can result in inconsistent fuel pressure leading to an abrupt shutdown.
Other Possibilities:
* Computer (PCM/ECM): While less common, a failing engine control module can cause unpredictable problems including sudden engine shutdown.
* Overheating: While less likely to cause *sudden* death, severe overheating can cause the engine to shut down as a safety precaution. Check coolant levels.
* Loose or Damaged Wiring: A short circuit or loose connection in the wiring harness can interrupt power to critical components.
Troubleshooting Steps:
1. Check the obvious: Battery terminals (clean and tight), fuel level.
2. Listen carefully when you try to start it: Does it crank at all? If it cranks but doesn't start, it points to electrical or fuel delivery issues. If it doesn't crank, it could be battery, starter, or ignition switch.
3. Check for diagnostic trouble codes (DTCs): Many auto parts stores will scan for codes for free. These codes can help pinpoint the problem.
4. Have a mechanic inspect it: If you're not comfortable working on cars, a professional diagnosis is essential.
Given the sudden nature of the failure, focus on the electrical system components initially, especially the crankshaft position sensor. However, a thorough diagnostic is needed to pinpoint the exact cause.
