AIR Pump

[lorpnek]

I just got my 2005 trailblazer back from the shop for a check engine light and they told me that I had a shorted emissions air pump and it was going to coast $530. Does anyone know how complex of a task this is or if there is a need for special tools. It would be great if I could do it myself.

[rodeo02]

Try a search for "air injection reaction, or AIR". The AIR system is on all 2004+ 4.2's. The hairdryer style 12VDC blower is under the truck, about under the drivers seat. On your 2005, you will see it grabs filtered air from a hose attached to the air cleaner flex pipe. The blower pressurizes this filtered air slightly and blows it into the check valve bolted just above the exhaust manifold, about center. That check valve is a common failure item. If it doesn't seal off, moisture from the exhaust gasses back flows into the blower housing. I'd check the electrical connectors at the blower and remove/clean the check valve. The check valve and blower are dealer only parts. I know the check valve is around $100.

Joel

[larry04tb]

Any idea how long the AIR pump should run when you start the TB?? I am getting a P0410 error code pointing to the pump but I hear it running. But it only runs for about 10 sec. I am wondering if thet is too short. I see there is a relay connection next to the pump. I wonder if controls how long it runs??

Thanks
larry

[rodeo02]

Larry, there is only one specific condition on my 2005 4.2L when I can actually hear the AIR system blower run. It's when the truck has been used to full warmup, then sits for 2-4hrs in temperatures below freezing. On the very next startup, the blower runs loudly for 10sec and shuts off. I'm sure the blower runs at other times, I'm just not able to detect it. If your blower is running, It has to be a stuck check valve. There is a post on another forum where the owner took the check vlv apart, cleaned it up, bench tested it with a 12VDC power source and put it back into service. Otherwise it's a $100 dealer only part.

Joel