* Fuel System Issues (without sensor failure):
* Fuel Pump Failure: A complete fuel pump failure will stop fuel delivery. However, the system may not always register this as a fault code immediately.
* Fuel Filter Clog: A severely clogged fuel filter can restrict fuel flow enough to stall the engine, but may not set a code until other related issues develop.
* Fuel line blockage or leak: A significant blockage or leak can starve the engine of fuel.
* Ignition System Problems (without sensor failure):
* Distributor Failure (older vehicles): A malfunctioning distributor can disrupt spark delivery to the cylinders.
* Crank Sensor Failure (intermittent): A failing crank sensor can sporadically prevent the engine from starting or running, but intermittent failures may not always log a code. This is more likely to cause a no-start than a stop-while-driving situation, but it's possible.
* Cam sensor Failure (intermittent): Similar to crank sensor failure, an intermittent camshaft sensor failure could cause this but may not always set a code.
* Electrical System Problems:
* Alternator Failure: While an alternator failure usually leads to a warning light, it's possible for the battery to be drained enough to cut power to the engine before that light triggers. This is more likely at lower RPMs or longer periods of driving.
* Poor Battery Connections: Loose or corroded battery terminals or cables can interrupt the electrical supply to the engine.
* Mechanical Issues:
* Broken Timing Belt (interference engine): A broken timing belt will instantly stop the engine in an interference engine (where the valves and pistons can collide). This is catastrophic and won't set a code in advance. Non-interference engines will just stop running.
* Seized Engine: A severely damaged or seized engine will simply stop.
* Transmission Issues (automatic): A sudden complete transmission failure could also cause the engine to stop, though this is less common.
Important Note: The absence of a check engine light doesn't mean there's no problem; it just means the problem isn't one that the computer's sensors are designed to detect and flag. Getting the vehicle diagnosed by a mechanic is crucial to determine the exact cause. They'll likely need to perform a more thorough inspection beyond just reading the codes.
