The horn no longer "toots" when I lock the doors of my 2001 Quest with the key fob remote. Nor do the lights flash when I unlock it
when locking car with remote horn does not sound on 2001 Nissan Quest
Check that the fob is set for SECURITY mode and NOT VALET mode, it does make a difference. Good luck.
Your key fob is set to "QUIET". Look at the back of your fob for instructions to set back to "honk" mode.