* Shift Interlock System: This is the most common cause. The system prevents the vehicle from shifting out of park unless the brake pedal is depressed and the key is in the "on" position (not just accessory).
* Brake Pedal Switch: The switch might be faulty or worn, not registering that the brake pedal is pressed. This is a relatively inexpensive and easy fix.
* Shift Lever Cable: This cable connects the shifter to the transmission. It could be broken, disconnected, or severely out of adjustment.
* Transmission Range Sensor: This sensor tells the vehicle what gear the shifter is in. A malfunction can prevent shifting.
* Steering Column Lock: In some cases, a problem with the steering column lock can interfere with the shift interlock.
* Transmission Problems: While less likely to directly prevent moving from Park, transmission issues can *indirectly* cause this.
* Low Transmission Fluid: Low fluid can cause various problems, including inability to shift. Check your fluid level immediately. Low fluid could also indicate a leak, which is a serious problem.
* Transmission Solenoids or Valves: Internal transmission components may be faulty, preventing the transmission from engaging.
* Internal Transmission Damage: More serious mechanical issues within the transmission itself could be at fault. This often involves higher repair costs.
Troubleshooting Steps:
1. Check the Brake Pedal: Make absolutely sure you're firmly pressing the brake pedal. Try pressing it very hard.
2. Check the Key Position: Ensure the key is in the "on" (run) position, not just the accessory position.
3. Check the Brake Pedal Switch: This is often located under the brake pedal. You may be able to access and test it (with a multimeter) or visually inspect it for damage.
4. Check the Transmission Fluid: Check the fluid level using the dipstick. If it's low, this is a serious issue that needs immediate attention. Note the fluid's condition – is it burnt or discolored?
5. Listen for Unusual Sounds: When trying to shift, listen for any unusual grinding, clicking, or whining noises. These can indicate mechanical problems.
6. Try Rocking the Vehicle: Gently rock the vehicle back and forth. Sometimes, this can free up a stuck mechanism. (Do this carefully and only if the brake is engaged!)
If none of these steps work, you should:
* Consult a Repair Manual: A repair manual specific to your 2002 Ford Expedition will provide detailed diagrams and troubleshooting steps.
* Take it to a Mechanic: If you're not comfortable working on your vehicle yourself, take it to a qualified mechanic for diagnosis and repair. They have the tools and expertise to pinpoint the exact cause and get your Expedition running smoothly again. Trying to force the shifter can cause further damage.
Ignoring this issue could lead to more extensive and costly repairs later. Address it promptly.
