P0492 - Secondary Air Injection System

[amdaman]

Hi all,

I got the above code about 500 miles ago (and a pending P0491) but now it came back quicker than before with just the P0492 so I think i'll have to look into it...

I've done a few searches and it looks like the most common cause is a vacuum leak. I've had my exhausts flap hoses disconnected and plugged for a while so this will be the fist place i'll check but does anyone know where the other common vacuum hose faults are? I do have a VCDS so i'll also be testing the pump when I get the chance.

Any common or obvious places to check (or pictures) would be greatly welcomed,

Cheers

[Gary(rs4)87]

Under the intake manifold,
If you standing opposite to the engine, on the middle there is T-pipe which one of them is connected in to the one way valve. That was the issue on mine and had a same issue like yours.

[amdaman]

Cheers Gary, did you have to remove anything to access the rear as from memory the engine goes right to the firewall!

[Gary(rs4)87]

This one is on the front so I’ve just removed the front end then I noticed that this pipe has split. So Iv ordered new vacuum pipe and fitted. All ok now

[eljay]

Awesome. Have the same errors plus stuck open flap so I presume something similar. Will check this weekend.

[amdaman]

I had a quick look at the hoses I could see and it all looked ok. The rear vacuum hoses were also plugged up with screws so it must be something I can't see, maybe at the front as Gary has suggested... or the pump its self.

Either way I couldn't be bothered to mess with it so it's at Audi now, they are going to check it out with their smoke machine.

I'll keep you posted.

[amdaman]

So Audi had a look, did the full vacuum line check with the smoke machine and also tested the pump which was all ok. They recommended I changed the relay so hopefully that sorts it!