What is this pipe?
Also, when I turn the car on "ON" and back off, I hear something in the engine compartment make a high pitch sound, almost like a whining sound that is spooling down or something. It doesn't do it when I actually star the car/turn it off. Anyone have any idea what that is?
The momentary high pitch noise when cycling the key is the air pump running a test. The AIR pump or Air Injection Reaction pump pushes fresh air into the exhaust when cold, this helps the catalytic converter start its chemical reaction faster to reduce emissions sooner in the drive cycle.







