I have just recently bought a 1996 F150 with the 300 6cyl engine. Before I bought the truck the guy had the truck inspected. After driving the truck for a day or so the check engine light came back on. The engine is throwing a code PO411. Can anyone help me to know what this code is and what I can do to get the check engine light off. The previous owner thought it had to do with the Air Pump. It didn't have a belt on the pulley and after putting a belt on it he had the same problem. Thanks for anyones help!

 

P0411 - Secondary Air Injection System Incorrect Flow Detected
Possible causes:
Faulty Vacuum hoses damaged
Faulty Air Pump inoperative Air bypass solenoid harness is open or shorted
Air bypass solenoid circuit poor electrical connection
Air bypass solenoid leaking/blocked or stuck open/closed
Air diverter valve leaking/blocked or stuck open/closed