Hey, this is the best answer and knowledge base about the secondary air system (i've check about 15 or 20 Threads from very long time ago) This is my problem (a little off-set from the creation of this Thread) with my Passat: B5 2.8 V6 30-valve, AHA:
Everything on my SAIS it's OK, except that the PUMP does not activate while the SAIS is working (cold start). The Pump is OK, I test it alone and it work with direct current, so I conclude that the PUMP is not the problem, as it is the current or power supply of the PUMP: I tested both wires that may activate the PUMP with a multimeter and both black and red wire measures GROUND, neither one gives +12V.
I've already checked the relay j299 (in the black box next to the brake fluid) and it's OK: it pass or bridge GROUND current from the Black Wire to the Black/Red Striped Wire (even when I don't know where this Black/Red wire goes to). I ignore if there is a FUSE or other things to check between the PUMP and the relay or other components. I read somewhere there is a FUSE near the relay j299 but I didn't found anything inside the black box.
About the other components of the SAIS, I tested them: the Kombi valve (Both) opens due to the vacuum generation, the PCV or PVC is new. This is the only Code I receive from the VAG-COM (i don't know the number right now) but it's related to the Secondary Air Intake or System, and obviously might be related to the Secondary Air PUMP that is not activated every time SAIS is working.
WHAT SHOULD I BE MISSING?
A good text I found is this one (in a 13 pages manual i have in pdf):
Secondary air system
The secondary air system blows air in behind the
exhaust valve for 65 seconds during the cold
start (+15 C - +35 C coolant temperature). This
produces an oxygen rich exhaust gas, causes
afterburning and reduces the heating-up phase
of the catalyst. Activation occurs from the
Motronic control module (J220) via the
Secondary Air Injection (AIR) pump relay -J299-
to Secondary Air Injection (AIR) valve -N112-
and combi-valve. Additionally after each
subsequent engine start (up to max. 85 C
engine temperature) the secondary air system
will after a 20 second delay switch in for 5
seconds during idling and will be checked by the
On Board Diagnostic (OBD).
sorry about my spelling, I'm from Central America, Guatemala, French.