Now secerty light is on and car won't start.

Hi Sharon, Welcome to 2CarPros.

This should be an easy fix for you. You just need the computer to relearn the new key cylinder. You just need to do the relearn procedure.

Make sure the battery if fully charged because this procedure may take up to 30 minutes and you cannot start the vehicle during this time. The instrument panel cluster (IPC). BCM and PCM must be in working order and the Passkey system repaired

1. Turn the key to ON and attempt to start the engine and release the key to the ON position.

2. The SECURITY light will illuminate. Wait 10 minutes until it turns off.

3. Turn the key to OFF for 10 seconds.

4. Turn the key to ON and attempt to start the engine. If it starts and run, the system has reset. If it doesn’t start or run and release the key to the ON position and complete the rest of the steps.

5. The SECURITY light will illuminate. Wait 10 minutes until it turns off.

6. Turn the key to OFF and wait 10 seconds.

7. Turn the key to ON and attempt to start the engine and release the key to the ON position.

8. The SECURITY light will illuminate. Wait 10 minutes until it turns off.

9. Turn the key to OFF and wait 10 seconds.

10. Start the engine

Let us know if this works for you.

Rich.