I have a 1996 F150 with the 4.9L engine. The bearing in my smog pump was going out so I put a new (remanufactured) smog pump on. A couple of days later, the check engine light came on. I read the code and it comes back P0411. Since this code corresponds to an inadequate flow in the secondary air injection I figured it was the smog pump, so I exchanged the smog pump for another and cleared the code. The next day, the check engine light came back with the same code. Seeing how I have replaced the smog pump twice, it doesn't appear to be the pump.

Any suggestions?

 

Check that the pump is drawing air in and delivery it . Also check that the bypass valve is functioning & has its vacuum supply working . If you remove the vacuum line from the bypass valve it should have vacuum once the engine has reached operating temp . Its a fairly simple system to diagnose .