I keep getting a P0411 on our 2008 Impala.... I have replaced the smog pump and the check valve....if anyone has a schematic for that I'd like to check all the circuits.....

Is there any carbon build up around the ends?

Neither..... I have replaced the pump and the check valve....... still have the P0411 code....driving me crazy.

I found the issue.... I had replaced the SMOG pump about a year ago and it worked fine, then stopped working.... I was discounting that BUT just to be safe I took off the hoses on the new pump and found that the pump was full of condensation water again and it burnt out motor..... the exhaust line condensation at start up keeps filling up this motor..... poor design by GM.

Common problem and yes it is one of the MANY bad designs.

Well . . . at least you found the problem.

Thanks for letting us know!