* Faulty ignition switch: This is the most common culprit. The ignition switch is responsible for breaking the electrical circuit when the key is removed. A worn-out or damaged switch might not be properly disconnecting the power, allowing the car to continue running.
* Problem with the ignition system: A short circuit or other malfunction in the wiring or components of the ignition system could prevent the power from being cut off when the key is removed.
* Steering column lock issue: Sometimes, problems with the steering column lock mechanism (which prevents the steering wheel from turning when the car is off) can interfere with the ignition switch's ability to properly disengage.
* Aftermarket additions or modifications: Improperly installed aftermarket accessories or modifications to the electrical system could inadvertently create a pathway for power to bypass the ignition switch.
* Stuck relay: A relay, which is an electrically operated switch, might be stuck in the "on" position, preventing the power from being cut off.
* Rarely: Faulty neutral safety switch (automatic transmission): This switch prevents the car from starting unless the gear selector is in Park (or Neutral). A malfunction could prevent the ignition from properly shutting off.
It's extremely important to have this problem diagnosed and fixed immediately. Driving a car that continues to run after the key is removed is dangerous and could lead to serious accidents or damage to the vehicle's electrical system. The engine could continue to run until it runs out of fuel, potentially causing a fire. You should avoid driving the car and contact a qualified mechanic as soon as possible.
