It showed up yesterday and I looked it up that it's the Secondary Air Injection System Switching valve stuck open. I cleared the code but this morning I heard the pump vacuum noise, which I have never heard before but the code didn't come back on. I found a $200 bypass unit that someone developed but is there a chance that it's an easier or cheaper fix or that it's just a glitch at the moment?
http://hewitt-tech.com/store/

 

If your area doesn't do emissions testing, or only looks at the OBD-II codes (no tailpipe probe) you can go with the bypass.

There's no reason to buy the $2000+ Lexus part. There's lots of threads here and on IH8Mud that detail how to use the Dorman OEM pump.

Chip H.

 

thank you Chip. Can you help me to understand what causes the loud vaccum cleaner sound all of the sudden?

 

what controls the valves to open and close? It can't just be a bad pump right? something must tell it to move.

 

If you go to http://www.lexussouthatlantaparts.com/ you can look up your year and the diagrams will show you the parts. Choose "Fuel, Exhaust and Emissions" then "Manifold Air Injection"

You'll see the pump, and two valve assemblies. The pump runs for a few seconds at startup to add additional air to the intake. The valves admit the extra air to the intake and prevent backflow.

Chip H.