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Discussion Starter · #1 · (Edited)
How many of you have a new S.A.S. Air Valve failure within 1 yr?

The story:
- Car is 1998 528i with 106K miles.
- In Jan. 2009, I replaced the S.A.S. Air Valve as a preventive measure (The S.A.S. system worked fine, no OBD codes at all). So for one year, no problem.
- This month, 2 codes came up: P1421 and P 1423, which is basically S.A. S. system fault. All along I thought it was Air Pump Relay and Air Pump but both checked out to be OK. I never thought it was the Air Valve because it is new.
- Finally I decided to disconnect the Large Hose (connected to Air Pump) and looked inside: sure enough the Air Valve Inlet side (where the Large Hose is attached to) is coated with black carbon sooth.
In other words, the Air Valve fails to close after the inital startup.
- So the diagnosis was clear: bad Air Valve, but I cannot believe this new Air Valve fails within 1yr/6K miles!!!



- I am glad I kept the Factory Air Valve. So the Factory Air Valve goes back in for now (very easy DIY: 10-mm nuts and that is it) and all is good.
- If the carbon builds up happens again, then I will go after the Electric Switch (which itself controls the vacuum).

The Morale of this story:
- Even new OEM part can fail faster than an 11 yr-old factory part!
- When replacing old parts that are still good (but you replace as a preventive measure), keep the old parts in your garage, never know you need to put them back in!
- Not a bad idea to include this as part of your routine maintenance: every 6 months or so, open the Large Hose and peek inside: if no carbon soiling, it is good. All it takes is 5 minutes to disconnect the Large Hose to look.

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1. For those who wonder what S.A.S. system is, read it up.
See the attached pdf for S.A.S. Diagnostic guide.

2. Some threads on P1421 and P1423 are here:
http://forums.bimmerforums.com/forum/showthread.php?t=291231
http://forums.bimmerforums.com/forum/showthread.php?t=1403066

3. For those who have Pierburg Air Pump problem and want to rebuild it, I wrote a rebuild DIY here:
http://www.bimmerfest.com/forums/showthread.php?t=402816
 

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I had the SAP replaced 3 times on my previous e39 over a 4+ year/50K period. One by the dealer under warranty and two by me, with the second one getting the pump replaced under parts warranty. I replaced the valve every time and I do not think the valve ever failed. Somehow, my previous e39 would spit out a SAP on a regular basis. Have had no issues with my current e39 so I am keeping my fingers crossed. Your morale of the story has a good tip for all DIYers. Hang on to those old parts. :thumbup:
 

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I still have the OEM part on mine as of now--was contemplating replacing it with a new one--don't know if I should after reading this post. CN90--was there any water coming out of the one you replaced when you removed it? Condensation is what kills the pump and that comes from the valve I understand.
 

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No part has a 100% perfect track record. There is always the occasional "bad one". The valve on my 2001 540 failed around 2004 under warranty...it took out the air pump as well. I recently replaced my valve as a preventive measure. I forget if I bought it from the dealer or not...but one good reason to purchase from the dealer; 24 month, unlimited miles warranty! AND, if it does require replacement, BMW will cover the labor to replace it too....just take the car to any BMW dealer. ;)
 
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