# Fault Codes 17831 & 17819, advice please



## Bartnik (Oct 26, 2000)

Hi folks,
My brother's '01 Passat V6 has the check engine light coming on and staying on steady. I scanned it today with VAG-COM and got the following 2 fault codes:
17831 - Secondary air injection system - Bank 1 - flow too low
17819 - Secondary air injection system - Bank 2 - flow too low
After scanning the fault codes I did output tests on the engine controller. The secondary air injection valve worked properly during the output tests (could hear it cycling) and the secondary air injection pump worked properly during the test (could hear it running).
So any ideas as to what the culprit could be? Perhaps an air leak in the system somewhere?
Thanks for any help.


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## Bartnik (Oct 26, 2000)

*Re: Fault Codes 17831 & 17819, advice please (Bartnik)*

Finally had a chance to troubleshoot this in-depth. Broke out the Bentley manual and the VAG-COM and got to work:
First removed the plastic hose from the air injetction pump to the top of the engine -- verified it was in good shape with no cracks or leaks.
Then ran output tests on the pump while the hose was off (man that thing moves some air!) and then again with the hose connected to the pump but not connected up top. Lots of air flow each time.
Finally tracked it down to a bad vacuum hose. The vacuum hose to the combi valve on the right side had dried out and split where it attaches to the combi valve. Couldn't see it until I took apart the air box and then the solution was obvious. This was the green fabric-covered vacuum hose which had become very brittle, I guess due to the heat under the hood.
The replacement hose (from VW) was a similar type but the fabric covering was black. Replaced each section of green hose (4 total) on each side and looks like that has done the trick. I also cut the new hose a bit longer than the original and that gave me some more slack on the run down to the combi valve -- now there is not such a tight bend in the hose where it turns around to plug into the valve, so hopefully that will put a little less stress on the hose and also will keep it away from hot parts.
Anyway, a little time spent troubleshooting the system with a good manual does the trick. Just FYI for anyone else who experiences this problem.


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