I remember meeting with a customer with the same complaint with a car that
was about 2 months old and still within the warranty coverage period.  The
dealer wanted to charge him a diagnostic fee since they suspected that
something fell into the receptacle, but the customer refused to authorize a
diagnostic fee since he thought that everything should be covered under
warranty.  I looked at the car, saw something in the receptacle, and fished
it out with the tweezers from my Swiss Army Knife.  I told the customer that
he was lucky that Toyota didn't charge customers for my services, and he
still thought that the car was defective because someone from the factory in
Japan had to have dropped the foreign object in there.  He clammed up when I
showed him the "foreign" object, a NH toll token and I politely explained
that it was unlikely that a Japanese factory worker would have NH toll
tokens in their pocket.