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.
-------------------------
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
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.
-------------------------
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