Rudyd

Can someone please post this manufacter letter. And does it apply to 2012 Q5 with 2.0 engine? Dealer claims they know nothing of this letter.

snagitseven

Does not apply to any 2.0T engine.

02AudiA6

Hello all, just got the dreadful CEL P0491 and P0492 code on 2012 Audi A6 3.0T Prestige. So does this definitely apply to the carbon build up issue. Is there a way to verify the problem? It has 56K miles on the car and it's a CPO so still under warranty for another year and up to 100K miles. Thanks in advance!

snagitseven

The codes are for the secondary air pump operation and should not have anything to do with the secondary air ports. It could be a bad pump or, more than likely, a leaking or broken secondary air pump pressure hose. The secondary air pump aids in reducing emissions during a cold startup (and could result in a failure of an emissions test until repaired). I've had to replace that pump on my wife's allroad).
Your CPO warranty should cover this issue.

Also note that if a CEL were to be caused by fouling of the secondary air ports, Audi will cover cleaning of the ports anyway through the SAP extended warranty until 100K miles but that is not your issue here.

02AudiA6

Thanks for the info. I saw there is a pump at the far bottom corner of the front bumper under the oil pan belly/side baffle at the driver side. Is that the SAP one? I want to check around it to make sure is not just a loose/or broken hose. I hated to bring it to the dealer unless it is something major like carbon buildup. I rather work on the car myself if it is not still under warranty. Thanks again.