2004 GMC Envoy P0410 Trouble Code

[glenrr]

This trouble code keeps coming up on my Envoy. Reading information about this code points to the pump not coming on as the primary problem. The pump comes on when the ignition switch is turned on so I'm at a loss as to what to do to repair this problem.

[carriedi]

the secondary air injection pump is designed to reduce exhaust emissions after initial engine start up. The computer does a test by turning things on and off to see if it's working like it should. It sees when it's working by looking at the oxygen sensor reaction. It wants to see the O2 sensor drop below 150mv. If the pcm doesn't see the correct drop it sets the code.

check the pump operation (key on engine off, turn the pump on and you should hear it come out the exhaust). Disconnect the hoses and check for water. Check the shut off valve, make sure it is opening and closing completely, they can get gunked up. Also check the O2 sensor operation. The O2 sensor is a common problem for this code too.