Secondary Air pump & valve

[tonycajjo]

Originally Posted by Weasel

The valve should have a small vacuum line going to it to activate/open the valve. That hose likes to get brittle and flaky to the point of breaking over the years... I'd check that hose first as it is a quick and easy fix if that is the case.

+1

this was my fix. just make sure you delete the codes. you can test the pump and the valve easily. you should be able to hear the valve actuate if you put a vacuum on the line via sucking on the one end. just dont do it while anyone is watching.

added: you could have a bad oxygen sensor, but i think it would throw other codes.

[yenanx5]

Originally Posted by tonycajjo

+1

this was my fix. just make sure you delete the codes. you can test the pump and the valve easily. you should be able to hear the valve actuate if you put a vacuum on the line via sucking on the one end. just dont do it while anyone is watching.

added: you could have a bad oxygen sensor, but i think it would throw other codes.

I replace the little hose from autozone last week, and the air valve from dealer $180. The SES light is gone. but today i went to autozone for the obd check, it show the same error p0492. The car drives quite noise from the engine and little vibrate at red stop without AC on.
How do you test the oxygen sensor?
Thankyou

[rayxi]

If you only get p0492 and not p0491 as well then it may be bank 2 oxygen sensor.

[pfhlaw]

I've been chasing this demon for months. Fault code is P0491 (secondary air pump flow bank 1). pump, valve, vacuum hose and solenoid are all good. Tried the seafoam trick (remove secondary air valve pour in 2 Oz. seafoam, replace valve then cold start) This confirmed the fault code because white smoke billowed out of the bank 2 side tailpipe but not the bank 1 side. I spotted 2 non-return valves (part no. 11121706921 one for each side) and I suspect that might be the problem.
Can anyone confirm that these non-return valves are part of the secondary air pump system?


RealOEM.com BMW E53 X5 4.4i Cylinder Head Attached Parts

[cmartin248]

Just to add another note to this,,, I recently replaced my own water pump on my 02 X5 4.4i with 115k miles.... I also cleaned the valve which causes code P0403... A short time later the SES light came back on and this time it was code P0491 and P0492. I read a lot of posts on here and had decided it was my recirculation valve, but some smart person said check the black with blue stripe hose that goes from the recirculation valve to a solenoid valve under the engine cover. This is a small vacuum line about the size of a pencil. To help find this hose, remove the engine cover, four 5 mm locking screws that only turn about a half turn. The hose is dead center on top of the engine. Trace the hose toward the front of the engine, and you will have to remove the breather tube from the air box to the throttle valve (about a 4" diameter tube). You will find the other end under the breather tube and attached to the valve. At first look everything seemed fine with the hose, but just before I decided nothing was wrong with it, I ran my finder under the connection to the recirc valve and found the cracked/broken hose. It looked perfect from above. Snipped about an inch off it and replaced it. Everything working fine.... thanks to all.....

[HamannE53]

My check eingine light just came on. I ran the code...P049, & P0492. Just did a full tune up about a week ago, Tech went down to the valley pan gasket, could they have triggered any codes by doing sloppy work or did I miss something when I decided to tune up the X? =\


BTW,...after my tune up I noticed very efficient fuel consumption and now seeing very inefficient fuel consumption. ..any common relations to these codes?

[Weasel]

Are those secondary air codes? I'd double check the vacuum line front the air valve to the solenoid under the engine cover.

[SLX5]

I have the same issue, read this post it may help

http://www.xoutpost.com/bmw-sav-foru...ump-valve.html

[HamannE53]

Shuckzzz...seems like a common problem. Guess we can add this to the legend of the Valley Pan gaskets, window regulators, and final stage resistors.

[cmartin248]

Check my post about 4 post up,, my codes p0491 and p0492 came in a few days after I replaced my water pump. While replacing the water pump, I apparently moved the small vacuum hose around and it cracked/split next to the recirc valve. Worth looking at due to your recent work...