Moto

About a month ago, my car pulled a CEL (16795 I think). Having an extended warranty, I took it to the dealer. They told me my secondary injection air pump had water in it. They want to replace Combi valve and the air pump ($1000 P+L not covered by my warranty of course).

I declined and had them reset the CEL. Since then the CEL has not come back. Each morning on cold starts, I hear the air pump come on for about 2 minutes and then go off.

What would cause water to get into the secondary air injection pump? Any suspect parts here? Would an intermittent air pump relay cause water build up? I think maybe once or twice I didn't hear the pump come on during the cold start cycle.

I've searched the forum, but couldn't draw any conclusions on this.

Thanks,

Daniel

TTschwing

From your airbox to the pump? Lower engine cover in place?

I'm curious as to how they determined it had water in it. It's riveted together, and in an awkward location. Not something you could easily check.

I'd skip their recommendations and see how it goes..Sounds like a money grab to me...

jhoeppel

ditto this. it's not like they disassembled it while in place (???)

ModifiedA4

this is from a Audi Tech Tip, for a different 1.8t, but the message is the same:

<i>"In the event you have an A4 1.8T with engine code ATW with the DTC of 16795 - Secondary Air Injection system, Incorrect flow Detected, a leaking Combination valve could be the problem. A leaking valve causes exhaust gas to enter the secondary air system. <b>The water from exhaust condensation travels through the entire secondary air injection system</b> and if the temperature drops below 0 degrees Celsius the water will freeze. <b>In most cases the water causes the air pump to corrode.</b> Inspecting the combination valve will reveal the problem. If the Intake side of the valve is black, exhaust has entered the secondary air injection system."
</i>

johnrw30VC5

You only need to pull the hose to tell if there is water in the punp, but I do agree most likely the combi valve is the culprit