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Secondary Air Injection fault 😕

alkrum001

New member
Location
Tel Aviv
Car(s)
1.6 Golf MK5
Hey everyone 🙂
I have a 1.6 102hp golf mk5 5spd.
recently the SAI System makes extremely loud noises in the mornings (like super hairdryer or something) and the CEL came up, returning code p0491.
What is the best solution? Can you just remove the system altogether? (I live in a relatively warm area where temperatures rarely go below 10 degrees Celsius and I’m not so sure I even need it)

Thanks for any advice 💪
 

Fred930

Scirocco MK II Track Car
Location
Wisconsin
First - I have a 2009 MK5 GTI 200HP 5 speed, and have never seen your exact model. But it's possible the SAI systems are similar, and the fact yours is making noise on startup indicates it may be running properly.

Assuming so, you need to carefully inspect the plastic hoses used to interconnect that system, looking for cracks or complete breaks. VW / Audi choose to use very poor materials for those plastic hoses, and I'm betting yours are broken, leading to the excess noise and fault code (which I did not look up). In fact, those hoses become so brittle with age that old ones seem to shatter with nothing more that a sideways "look".

Similar poor technology plastic hoses are used on the PCV system.
 

alkrum001

New member
Location
Tel Aviv
Car(s)
1.6 Golf MK5
First - I have a 2009 MK5 GTI 200HP 5 speed, and have never seen your exact model. But it's possible the SAI systems are similar, and the fact yours is making noise on startup indicates it may be running properly.

Assuming so, you need to carefully inspect the plastic hoses used to interconnect that system, looking for cracks or complete breaks. VW / Audi choose to use very poor materials for those plastic hoses, and I'm betting yours are broken, leading to the excess noise and fault code (which I did not look up). In fact, those hoses become so brittle with age that old ones seem to shatter with nothing more that a sideways "look".

Similar poor technology plastic hoses are used on the PCV system.
Thanks a lot! What’s your opinion about just deleting the system? I’ve read about a few E36/E46 owners who have done this but not VAG Owners.
 

chorales

New member
Location
iowa
Car(s)
2009 GTI
Thanks a lot! What’s your opinion about just deleting the system? I’ve read about a few E36/E46 owners who have done this but not VAG Owners.
Mine was deleted by the PO on my 2009 GTI so I will have the MIL on for the rest of it's life unless I find a way to get it tuned out. My understanding of the SA system is it's just to help get your cat to heat up faster or something, doubtful there would be any noticeable changes in having it there or removed, other than the MIL..
 

Mk5Steven

New member
Location
Temecula
Car(s)
2009 PZEV GTI
I just fixed this code with 1K0131128D “4” in the attached photo of the SAI system
9938767F-F3C4-4346-A76A-A4B55A1241C2.jpeg
 
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