Help with Secondary Air Injection (SAI) Codes

B6/7 S4/RS4
#1

So I just finished my first carbon clean, got everything put back together. I also replaced the air filter, cabin air filter, spark plugs, and did an oil change. The car had been sitting for months, the battery was dead. I charged the battery and she started up immediately, no codes (I guess due to battery being dead). That was about 1 week ago, since then I’m getting the following code:

001169 - Secondary Air Injection System: Bank 1
P0491 - 002 - Insufficient Flow - MIL ON
Freeze Frame:
Fault Status: 11100010
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 65482 km
Time Indication: 0

         Freeze Frame:
                RPM: 1149 /min
                Load: 47.8 %
                Speed: 14.0 km/h
                Temperature: 28.0°C
                Temperature: 21.0°C
                Absolute Pres.: 980.0 mbar
                Voltage: 13.208 V

I’ve cleared it twice and its come back. So this weekend I will try and look into this, so I’m here looking for advice as to what I might look for? Insufficient flow, does that imply a leak? blockage? something else? Any suggestions as to where I should start?

Also, based on my research, the SAI system appears to be a mostly useless system. So removing it altogether might also be an option?

I’m wondering as well, if the check engine light is on (as it is when I get this code) is the engine/ECU in some sort of safe mode? ie even if this is a non critical system, will performance be affected if this code is up?

Thanks

#2

Codes like that are usually because of vacuum lines either being damaged or disconnected. It is fairly common for codes like this after taking an intake manifold off. The secondary air combination valves need vacuum to work properly so trace the lines from the valves in the back to find the problem.