Can you help diagnose this Peake code: Secondary air system flow too low
 

3.0i M54 engine keeps tripping the Service Engine Soon light.
Peake engine code tool reports two errors. They're both basically the same, just different cylinders:

F5: Secondary air system flow too low, cyl 1-3
F6: Secondary air system flow too low, cyl 4-6

If I reset it, its gone for a few day, then SES light back on.

Do you know what this could mean / which part might be failing, or which electrical connection to check? Or, keeping in mind, I guess it could just be a sensor that is going out and reporting falsely.

Thanks so much.

It sounds like there is a leak in the secondary pump. Check the hoses on the pump to make sure you don't have a leak. It being too low sounds like its on the output side and air is escaping. Feel around on the hoses from the pump and make sure there aren't any leaks.

My guess based on what had happened to me, is the vacuum line to the vacuum switch that operates the switch to the pump has perished and will crumble in your hands. A very cheap fix if you do it quickly. (Cost less than $5 at Autozone for vacuum tube.) If you leave it you could end up having to replace the Secondary Air Pump. (About $350 at Bavauto at the time.)
Check on RealOEM for a diagram of the SA System and you'll see the tubing.
GL.

Hey, just wanted to say thanks guys. I looked up the schematic for the secondary air flow pump like you said, studied all the parts, inspected my engine bay, and I think I see the problem; The vacuum tubing just after the metal housing pump is very nearly crumbly. Very old looking. The intake side 1" rubber tubing into the plastic pump was loose as well. I think I just need to get some of these tubing parts replaced. 96k... they're probly fried, or soon will be.

So thank you so much. The knowledge level on this forum is so high. Awesome group!

- R

mental note to reply to all 'while I'm here, what else should I look at' posts, heheh..

That secondary air-pump for emissions leaves a nice SES light on until you replace it, obviously stopping you from getting that message when you really need it.. and a relatively easy preventative maintenance that even the stealer doesn't do. Since it winds up crumbly, is this a candidate for SS tubing?

<sigh>