On the 2.8 there's two valves sitting atop the throttle body by all the vacuum tubes:



Every place I look lists them under a different name

Both: Solenoid valve (via)

Left: Secondary Air Injection solenoid valve, Right: Intake Manifold Tuning valve

Left: Secondary Air Injection solenoid valve (N112), Right: Intake manifold change over valve

ECS even has them listed as the N249 valve, which I thought was only used on 1.8t's (when above they are listed as the N112 valve)

Audi part #'s: 026906283J ; 026906283H; 026906283D; 026906283G; 026906283H; 028906283H; 028906283H

Suffice to say, I'm confused.

Do they do the same thing? If I replace one should I replace both? One obviously has a green connection and the other blue.

Keep in mind that every place shows them looking like the exact same item.

If anybody has experience with this part of the vacuum system, please shed any light.

Thanks!

 

I don't know the 2.8, but on the 1.8T there are two of them: one is the N249 (diverter valve control), and the other is the N112 (secondary air injection control). They're the exact same part, but used in different systems.

Can you trace the vacuum lines coming off of them?

 

I'm think it must be the same for the 2.8


They're numbers 17 and 5

 

As mentioned I'm not very familiar with the 2.8. That said:
1) is #9 the vacuum reservoir?
2) Looks #7 & #15 are SAI valve, so then the purpose of solenoid #17 (blue connector) is to open the combi valves and allow fresh air into the exhaust.
3) Do you know the description for #11? Looks like that's what solenoid #5 (green connector) is responsible for. I think the 2.8 might have a "changeover valve" or something like that, which actuates flaps within the intake manifold. But I could be wrong and/or the flaps are actuated by an electric motor.

 

Right sorry I forgot the legend:

But yes you got them all right so far


1 - Ventilation line to fuel tank

2 - Evaporative Emission (EVAP) canister located at bottom of spare wheel well underneath vehicle

3 - Leak detection pump located in left-rear wheel housing

4 - Air cleaner for leak detection pump (LDP)

5 - Intake Manifold Tuning (IMT) valve to vacuum solenoid of intake manifold tuning valve

6 - Fuel pressure regulator

7 - Combination valve, left for Secondary Air Injection (AIR) At rear of left cylinder head

8 - Engine

9 - Vacuum reservoir

10 - Intake manifold

11 - Intake manifold tuning vacuum solenoid for intake manifold tuning valve

12 - Secondary Air Injection (AIR) pump motor -VOA- intake air from air cleaner

13 - Air cleaner with connection for intake air for secondary air injection pump

14 - Throttle body

15 - Combination valve, right for secondary air injection located at rear of right cylinder head

16 - Check valve

17 - Secondary Air Injection (AIR) solenoid valve -NIH- Control line to combination valves left and right

18 - Evaporative Emission (EVAP) canister purge regulator valve mounted to air cleaner housing


Yeah that's one of the names these two valves fall under in my OP, so you can see the confusion I'm having.

 

When I said "changeover valve", I meant "changeover flap", which is part of the intake manifold tuning system.

Pretty sure in this case those 2 valves on the 2.8 are the same part and interchangeable, based on our discussion. I'm assuming on your car they both share the same part number?

How come you're looking to replace one or both? Since they're used in different systems I wouldn't replace both just because one is bad.

 

Oh no, I'm only looking replacing the one (#17 above, green connection), I got a p0403 code

P0403 Audi Exhaust Gas Recirculation Control Circuit OBDII Engine Light Trouble Code | Engine-Codes.com

It may very likely be the EGR valve itself but from what I can tell, those are nearly impossible to replace on a 2.8. I tried for help, but couldn't find any