Bill had a check engine light on his 00 A8, with the fault code being:

2 DTC's Found:
17831 - Sec. Air Inj. Sys: Bank 1: Flow too Low
35-00 - -
17819 - Sec. Air Inj. Sys: Bank 2: Flow too Low
35-00 - -

I had never heard of the air injection pump (The ABZ engine does not have the system, only the 00 and newer cars have it), but we found it in the airbox, on the suction side of the air filter.



The Bently says to check the hoses and make sure the fuse is good and the motor works. Hook up the ross-tech software, do an output test and it starts testing all the components in the fuel injection system!

Get to the one for the air injection pump, it pulses 12 VDC to it and you can hear it spinning. But it doesn't seem to have any airflow, like whatever it is discharging into is closed. So we follow the hose and find that it goes here (hose is removed in picture, but the hose was just fine).



So we pulled the hose as shown in the picture above and did the output test again, and that air pump was blowin'!!!

So we looked at where it went and found that the diaphrams have to be activated to have the valve open and allow air flow. There is one at the aft end of each cylinder bank. What controls the diaphram you ask?

A vacuum line. So we follow the vacuum line and see that it goes here, which is on the top side of the left cylinder bank, mounted on the aft side of the fuel rail.



Guess what??? The vacuum hose was disconnected, for some reason it was too short to reach it, we did a little rerouting of the hose and got it connected again.

We also did an output test of the Solenoid 112 and found it was working. However, with no vacuum supply to the solenoid valve, it couldn't open the diaphrams which allows air from the air injection pump to discharge into the cylinder bank or exhaust or where ever it goes (Randy explained the purpose to us the other day). It's amazing how you stop when you find the problem.

Cost for the repair???

$8 worth of lunch meat for myself and Floris for lunch.

Cost for the repair at the stealer???

Bill was quoted $350 for a new pump and motor, however, it was working just perfectly, some monkey lad must of disconnected that vacuum line along the way, you could tell somebody had been in there before.

Another Triumph!

pw

_________________________________
Paul Waterloo
01 S8 Black on Black

Lots of Electronic Mods

D2 A8/A8L/S8 FAQ Digest