Fixing the Key Fob Not Working Issue on a 2021 Ford Explorer

Step 1: Check Battery

1. Visual Inspection: Examine the key fob for any physical damage or signs of wear.
2. Battery Test:
   • Tools Required: Small Phillips screwdriver, new CR2032 battery (or appropriate battery for your fob).
   • Procedure:
     1. Open the key fob using the screwdriver by unscrewing the screws or gently prying it apart.
     2. Remove the old battery and inspect for corrosion or leakage.
     3. Use a multimeter to check voltage (should be around 3V).
     4. Replace with a new battery if the voltage is low or if the battery is corroded.

Step 2: Reprogram the Key Fob

If the battery is functioning correctly, the fob may need to be reprogrammed.

1. Procedure:
   • Tools Required: None specifically, but having a second working key fob can expedite the process.
   • Steps:
     1. Enter the vehicle and close all doors.
     2. Insert the key into the ignition and turn it to the "On" position (do not start the engine).
     3. Turn the key back to the "Off" position and remove it.
     4. Within 10 seconds, insert the key back into the ignition and turn it to the "On" position again.
     5. Repeat this process 3 times (On, Off, On, Off, On).
     6. After the third time, leave the key in the "On" position. The door locks should automatically cycle, indicating the vehicle is in programming mode.
     7. Press any button on the key fob you want to program. You should hear a confirmation sound.
     8. Repeat this step for any additional fobs.
     9. Turn the ignition to the "Off" position to exit programming mode.

Step 3: Inspect Vehicle Systems

If the key fob still does not work after replacing the battery and reprogramming:

1. Tools Required: OBD-II scanner.
2. Procedure:
   • Use an OBD-II scanner to check for any fault codes related to the keyless entry system or ignition system.
   • Look for codes like B124A (related to key fob) or other relevant codes.
   • If codes are present, document them for further diagnosis.

Step 4: Check for Interference

Sometimes, electronic interference can cause the key fob to fail.

1. Procedure:
   • Move away from electronic devices or other vehicles that may be causing interference.
   • Try using the fob near the vehicle to see if functionality improves.

Step 5: Inspect Vehicle Antennas

If the key fob is still not working, there may be an issue with the vehicle's receiver or antennas.

1. Tools Required: Multimeter, basic hand tools.
2. Procedure:
   • Inspect the wiring harness connected to the keyless entry module located under the dashboard.
   • Check the antenna located in the roof or the rear hatch area for damage or disconnection.
   • Use a multimeter to test for continuity in the wiring.

Repair Instructions

Replacing the Key Fob

If all diagnostic steps fail, consider replacing the key fob.

1. Purchase a New Key Fob: Obtain a new key fob compatible with the 2021 Ford Explorer.
2. Programming the New Key Fob: Follow the reprogramming steps outlined above to program the new fob.
3. Test the New Key Fob: Ensure the fob controls door locks and starts the vehicle as intended.

Conclusion

By following these detailed steps, you should be able to diagnose and resolve the key fob issue on your 2021 Ford Explorer. If the problem persists after all these troubleshooting steps, it may be necessary to consult a Ford dealership or a professional automotive locksmith for further assistance.