There could be several possible reasons why your Honda Pilot is refusing to start. Let's go through some common troubleshooting steps that might help you identify the issue:

1. Check the battery: A dead or weak battery is often the primary reason for a car not starting. Check if the battery terminals are tightly connected and not corroded. If necessary, try jump-starting the vehicle using jumper cables and another car with a working battery. If the car starts with a jump, it is likely that the battery needs to be replaced.

2. Inspect the starter motor: The starter motor is responsible for cranking the engine and initiating the combustion process. If you hear a clicking sound when you turn the key, it could be a sign that the starter motor is faulty. In this case, the starter motor might need to be repaired or replaced.

3. Verify the fuel system: It's possible that your Honda Pilot is not getting fuel to the engine, preventing it from starting. Check if there is enough fuel in the tank. You can also try listening for the fuel pump when you turn the key to the "on" position. The fuel pump should make a humming sound for a few seconds. If you don't hear anything, the fuel pump might be malfunctioning.

4. Examine the ignition system: The ignition system includes components like the ignition coil, spark plugs, and ignition switch. If any of these components are damaged or worn out, it can cause starting issues. Inspect the spark plugs to see if they are fouled or worn. If necessary, replace them and check the ignition coil as well.

5. Check the security system: In some cases, the security system can prevent a car from starting, especially if there is a problem with the key fob or the immobilizer system. Make sure the key fob has a functioning battery and try using the spare key, if available.

If none of the above troubleshooting steps resolve the issue, it is recommended to have your Honda Pilot diagnosed by a qualified mechanic or bring it to a Honda dealership for further inspection. They will have the necessary tools and expertise to identify and fix the problem accurately.