Igintion key will not eject

The issue you are describing with your 2000 Dodge Grand Caravan, where the dash says "reverse" when the vehicle is actually in "park" and the key can be removed while the engine is running, is likely related to a problem with the vehicle's transmission range sensor or park/neutral safety switch.
The transmission range sensor is responsible for sending a signal to the vehicle's computer indicating the position of the transmission shift lever. If the sensor is malfunctioning, it may send an incorrect signal to the computer, causing the dash to display the wrong gear position.
The park/neutral safety switch is responsible for preventing the engine from starting or the key from being removed when the transmission is not in the "park" position. If the switch is malfunctioning, the engine may start and the key may be removable even when the transmission is not in "park".
It's best to diagnose the problem by a professional, or if the vehicle is still under warranty, contact the manufacturer for assistance. It's important to note that these are general steps and the specific procedures may vary depending on the exact model and type of your vehicle. It's recommended to consult the user manual or contact the manufacturer for the specific instructions and precautions for your vehicle.

Does the vehicle start an run ?Can you turn the key to the off position ? And the key won't come out ? Did you try some key graphite ( lube ) ? New lock cylinder need maybe . Or is it a problem with
Steering Column Electric Park Lock
If the vehicle is equipped with a floor-mounted console gear shifter, an added safety feature is an steering column electric park lock system in the steering column. The steering column electric park lock system prevents the steering wheel from being locked when the transmission is in gear and the vehicle may be moving. The column ignition lock system consists of a steering column electric park lock and a park position switch, that is located in the A/T shift lock control switch. The steering column electric park lock contains a spring-loaded pin that mechanically prevents the ignition key cylinder from being turned to the Lock position when the transmission is not in the Park position. If vehicle power is lost or the transmission is not in the Park position, the operator will not be able to turn the ignition key to the Lock position and will not be able to remove the ignition key from the column.

What make vehicle ? Most all vehicles have a safety system .Don't try an force anything you'll break it !
Electronic Park Lock (EPL)/Ignition Lock Cylinder Control Actuator: If the vehicle is equipped with automatic transmission and a floor mounted console gear shift, it has an ignition lock cylinder control actuator system in the steering column. The ignition lock cylinder control actuator purpose is to prevent the ignition key from being turned to the OFF position when the transmission is in any position other than PARK and the vehicle may still be moving. The column ignition lock system consists of an ignition lock cylinder control actuator, and a park position switch that is located in the automatic transmission shift lock control switch. The ignition lock cylinder control actuator contains a pin that is spring loaded to mechanically prevent the ignition key cylinder from being turned to the lock position when the vehicle transmission is not in the PARK position. If vehicle power is lost, and/or the transmission is not in the PARK position the operator will not be able to turn the ignition key to the lock position and will not be able to remove the ignition key from the column. They also have this on column mounted shifters !

Most if not all vehicles have a Electronic Park Lock (EPL)/Ignition Lock Cylinder Control Actuator: If the vehicle is equipped with automatic transmission and a floor mounted console gear shift, it has an ignition lock cylinder control actuator system in the steering column. The ignition lock cylinder control actuator purpose is to prevent the ignition key from being turned to the OFF position when the transmission is in any position other than PARK and the vehicle may still be moving. The column ignition lock system consists of an ignition lock cylinder control actuator, and a park position switch that is located in the automatic transmission shift lock control switch. The ignition lock cylinder control actuator contains a pin that is spring loaded to mechanically prevent the ignition key cylinder from being turned to the lock position when the vehicle transmission is not in the PARK position. If vehicle power is lost, and/or the transmission is not in the PARK position the operator will not be able to turn the ignition key to the lock position and will not be able to remove the ignition key from the column. Or it has
Linear Shift Assembly: If the vehicle is equipped with a column mounted gear shift, it has a linear shift assembly on the steering column. The linear shift assembly has a cable that runs from the linear shift assembly to the ignition lock cylinder case. The purpose of this cable is to prevent the ignition key from being turned to the OFF position when the transmission is in gear and the vehicle may still be moving. The linear shift assembly cable contains a pin that is spring loaded to mechanically prevent the ignition key cylinder from being turned to the lock position when the vehicle transmission is not in the PARK position. If vehicle power is lost, and/or the transmission is not in the PARK position the operator will not be able to turn the ignition key to the lock position and will not be able to remove the ignition key from the column.
Your best bet is to take it to a ASE certified repair shop or the dealer ! The fix involves taking the steering column apart an or the floor shifter assembly ! Also electrical test to determine what is the problem !
Your

go to a service, you may have trouble parking sensor, contacts, etc.

ask at the dealer i think it may only need a new stop light switch but i could be wrong ,how about leaving the car in neutral ,does key come out then as should do but later cars like this it might not work in neutral though

I have worked on several vehicles with this same problem and each one was a relatively simple repair with no parts involved, first off the shift interlock has nothing to do with it and will not prevent your vehicle from going into park, it is designed to work ONLY when coming out of park. The problem your having depends on the type of shifter handle your vehicle has, if the release lever is on the bottom and you have to push up with your fingers to release it, then the problem is...there is a rubber type cover that surrounds the release button, after time it becomes distorted and bunches up preventing the shifter from fully engaging in the park position (even though it appears the vehicle is going into park)if your careful you can work the rubber cover out and your problem is fixed. If your shifter button is on the side and pressed with your thumb the cable needs to be adjusted, this cables only purpose is to prevent key removal except when in park and is easily adjusted, with the center council removed, if you look at the front of the shifter base you will see 2 cables that snap into the shifter frame, the larger one is the gear selector cable, the smaller one runs up to the steering column and operates the mechanism that prevents key removal, where the cable snaps into the shifter frame is where the adjustment is done and is identical to a kick-down cable used on older vehicles with automatic transmissions, right where it snaps into the frame there will be a button you can press down releasing a spring loaded adjustment arm, make sure you first mark the arm for reference then press down the button and adjust it a little either way until it functions properly, hope this helps and good luck   

If disco is automatic move the transfer lever from high to low box and back again firmly then the key will come out there is a safety feature on the autos to prevent the key being removed if the transfer box is not in either high or low correctly with most dicso;s the transfer shift lever is stiff. through lack of use .once it is pushed in properly the key will release it works every time and I have had four v8 autos
basically you cant remove the key because even though the gearbox is in park if the transfer gears are not fully home the park sensor on the gearbox thinks it is out of gear eg not in park so wont let you remove the key and leave the car out of gear in case it rolls away .Dan

The transmission range sensor is malfunctioning. The range sensor tells the computer what gear the selector lever is in. If it will not read the park position, it will not disengage the interlock system. Take it to a good repair shop that you trust and have them check the function of the sensor. Good Luck.

help! the key ignition is stuck in off and we can't get it to turn to on.