Where's the air pump?

[CaptSeaweed]

Hi all,

Just joined "Forums" today, and think it's a great site. I have a problem with a 2004 GMC Envoy SLT (V6). I got a code PO410 (secondary air problem), and after doing some research, find that the problem is most likely with the pump, or check valves. Does anybody know where exactly the air pump is physically located? Also, where are the check valves located? Thanks for any help. Additional info, is more than welcome.

[maxwedge]

Welcome to AF, under the body l/s below the drivers seat on the frame rail. Also check the fuse, the pump can freeze up from a bad check valve also.

[CaptSeaweed]

Hi all,

I found the air pump. removed it from the vehicle, and put 12 volts to it. Ran like a champ. I replaced it on the vehicle, and followed the inlet and outlet hoses to the check valve, where I found the electrical connector disconnected. Apparently, the GM tech who replaced the spark plugs didn't put it back correctly.
I am hoping that someone can explain to me why there are wires going to a check valve. I am an industrial mechanic, with 30+ yrs experience, and I can't recall ever seeing an electrical check valve in a hydraulic or pneumatic system. Thanks for any help!

[BRD]

Glad you got it solved. I had a dealer's tech once forget to hook the horn back up. Stuff happens. I would have said check the gas cap before anything else. If it's loose you can get that same code. It doesn't tell you much except there's a vacuum fault somewhere. Why wires to a check valve? Good question. I can only GUESS it's to send error info to the PCM if there's a malfunction in the AIR, which is a PITA when it goes out.

[CaptSeaweed]

Glad I got it solved, too! It's my girlfriend's car, and she was kinda concerned, to say the least. <G> Guess I need to get my head out of 70's and 80's technology. Last time I had a smog pump problem, it was mounted on the front of the engine, and was belt driven. The pre- OBDII days, when repair options were as limitless as the mechanic's creativity!
Getting back to the check valve. I'm not so sure that it's a check valve. I think I read on another forum that it's actually a solenoid actuated valve. That would make more sense. Either way, we put 100 miles on the car yesterday, and no "Check Engine" light! BooYah!!

[GMMerlin]

Originally Posted by BRD

Glad you got it solved. I had a dealer's tech once forget to hook the horn back up. Stuff happens. I would have said check the gas cap before anything else. If it's loose you can get that same code. It doesn't tell you much except there's a vacuum fault somewhere. Why wires to a check valve? Good question. I can only GUESS it's to send error info to the PCM if there's a malfunction in the AIR, which is a PITA when it goes out.

Dude you have absolutely no idea what you are talking about. A loose gas cap will not cause a P0410 code to set.
2 entirely different systems with 2 entirely different sets of DTCs.
The Check valve is not a check valve but a solenoid valve which is controlled and monitored by the PCM.
It is a 5 wire solenoid/sensor assembly. 2 wires control the valve and 3 wires are from the sensor that relate the position of the valve back to the PCM

[CaptSeaweed]

Thanks for the update , Merlin. I really hate not knowing what makes things tick!