* Faulty ignition switch: This is a common culprit. The switch might be worn out, broken, or malfunctioning, preventing it from properly interrupting the electrical circuit to the engine.
* Problem with the neutral safety switch: This switch prevents the car from starting unless it's in park (or neutral, depending on the transmission). If it's faulty, it might not be sending the correct signal to the ignition system, even if the key is turned to the "off" position.
* Electrical issue: A short circuit or a problem in the wiring harness could be keeping power flowing to the engine even when the key is off. This could involve any number of components.
* Stuck or faulty starter: While less common, a stuck starter could continuously crank the engine, even when the ignition is off.
* Vacuum leak: Some older vehicles use vacuum systems to control various functions. A severe vacuum leak could prevent the engine from shutting down properly. This is less likely on a Saturn but still possible.
* Computer (PCM) issue: The Powertrain Control Module (PCM) or Engine Control Unit (ECU) could be malfunctioning. A faulty PCM could fail to send the "engine off" signal properly.
* Faulty crankshaft position sensor: This sensor tells the computer where the crankshaft is. If it's faulty, the computer might not know when to shut off the fuel supply.
What to do:
1. Safety First: If your engine won't shut off, pull over to a safe location as soon as possible. Avoid turning the steering wheel if the engine is still running as this might cause power steering failure.
2. Try the basics: Turn the key firmly to the "off" position, multiple times.
3. Check the transmission: Make sure the car is in "Park" (automatic) or "Neutral" (manual).
4. Disconnect the battery: This is a last resort, but disconnecting the negative (-) terminal of the battery will definitely shut off the engine. However, you'll need to reconnect it once the problem is fixed, and you'll likely lose your radio presets and possibly other settings.
5. Call a mechanic or roadside assistance: Attempting to diagnose and repair this yourself could be dangerous. A qualified mechanic can properly diagnose the issue and make the necessary repairs. Don't attempt any electrical work unless you have significant automotive experience.
Important Note: The year and model of your Saturn is crucial information for accurate diagnosis. The specific issues and solutions vary between different Saturn models. Providing this information will allow for more targeted assistance.
