2 days ago, cel came on. so i took it to advance cuz i was curious. car was running normal. code p1516 came up - idle speed control. okay i made an appt for the following day. well the following day (yesterday) cel goes away. i was told my a gm mechanic that the p1516 code is something is up with the throttle system. Well, dealer decided to change the ecm.

Anyone know why they would change the ecm? Maybe the mechanic didnt find anything wrong with the throttle system and thought the ecm was bad?

By the way, whats the warranty on rust for our cars and does it include the body side moldings and door edges?