For 1990-2009 cars

The ignition switch has four different positions.

To shift out of P (Park), the ignition must be in ON/RUN or ACC/ACCESSORY and the brake pedal must be applied.

Notice: Using a tool to force the key to turn in the ignition could cause damage to the switch or break the key. Use the correct key, make sure it is all the way in, and turn it only with your hand. If the key cannot be turned by hand, see your dealer/retailer.

(LOCK/OFF): This position locks the ignition and steering column. The key can only be removed in LOCK/OFF. If you have an automatic transmission, the ignition switch cannot be turned to LOCK/OFF unless the shift lever is in P (Park). If you have a manual transmission, the ignition switch can be turned to LOCK/OFF in any shift lever position.

Caution: If you have a manual transmission removing the key from the ignition switch will lock the steering column and result in a loss of ability to steer the vehicle. This could cause a collision. If you need to turn the engine off while the vehicle is moving, turn the key to ACC/ACCESSORY.

ACC (ACC/ACCESSORY): This is the position in which you can operate some of the electrical accessories. It unlocks the steering wheel and ignition.
(ON/RUN): This position can be used to operate the electrical accessories and to display some instrument panel cluster warning and indicator lights. The switch stays in this position when the engine is running. If you leave the key in the ACC/ACCESSORY or ON/RUN position with the engine off, the battery could be drained. You may not be able to start the vehicle if the battery is allowed to drain for an extended period of time.
(START): This is the position that starts the engine. When the engine starts, release the key. The ignition switch returns to ON/RUN for normal driving. A warning tone will sound when the driver door is opened, the ignition is in LOCK/OFF or ACC/ACCESSORY and the key is in the ignition.