05 GMC Envoy PO410 code.

bfd1262 · 08-29-2009, 03:00 PM

Have replaced relay for air pump and air pump works now. Reset code and a day later code comes back on. I can hear the pump running if I shut the vehicle off right away. What else could it be?

Airjer_ · 08-29-2009, 05:20 PM

I would bet that the switching valve is stuck closed.

maxwedge · 08-29-2009, 06:02 PM

Agreed.

Airjer_ · 08-30-2009, 10:03 AM

You can unplug it and hook a power wire to one terminal [of the switching valve and another jumper to ground on the other terminal. Make sure you are doing this on the switching valve! You should hear a click when you supply and remove power. With power supplied and the air supply hose from the pump disconnected from the valve you can start the vehicle. You should hear/feel exhaust gas coming out of the tube the air supply connects to. If you don't than replace the valve.

bfd1262 · 08-30-2009, 10:22 AM

Great thanks. Where is this switch valve located. Pass. side of the engine?

Airjer_ · 08-30-2009, 01:18 PM

passenger side right above the exhaust manifold towards the rear. You'll see the big fresh air hose going to it.

bfd1262 · 08-30-2009, 01:38 PM

Found it. Thank you!
Would you happen to know the part number for this?

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