While troubleshooting P0491 and P0492 error code.

[RdRunner666]

Hi Guys,

 

Sorry for the multi topic discussion; The check engine light just came on (01 996 45Kmiles) with the codes P0491 and P0492, I cleared it with those OBDII checkers from O-Reilly, and it comes back every 100 miles or so, 3rd time now.  (In which I still don't know what causes it) over the weekend I just checked the hoses, and they seen fine. ANY IDEAS?

 

While on the process of checking the the hoses "the little tubes that connects to the diverter valves" (Billet forged installed in 05 @ 30Kmiles) I had to remove the boost hose, and found engine oil inside the boost hose, about maybe 2 table spoon of it inside the bottom where they connect. I also stuck my fingers inside, and looks like it's "around" the inside of the hose (all over). But the interesting is, it's only on my (left hose "driver side"). I also checked the (right side "Passenger side" and it was clean). 

 

What caused the oil to get in there? Also could this be the cause of the Error Code?  Any ideas?

 

Thanks

 

 

[JFP in PA]

Welcome to RennTech.  I don't think your codes the oil issue are necessarily related.  As for the codes:

 

P0491 Secondary Air Injection System, Bank 1 - Insufficient Flow

P0492 Secondary Air Injection System, Bank 2 - Insufficient Flow

Possible cause of fault

- Electrical fault in power supply or line between relay and secondary air injection pump

- Secondary air injection pump relay mechanically faulty

- Mechanical fault in electrical secondary air valve

- Pneumatic secondary air valve faulty/sluggish

- Electrical fault in secondary air injection pump

- Mechanical fault in secondary air injection pump or secondary air injection pump blocked

- Vacuum system leaking

- Air hose to secondary air injection pump slipped off or constricted

 

 

[RdRunner666]

Thanks JFP,  any DIY instructions on how to check the other stuff, other than the vacuum hoses?

 

-Ryan

[JFP in PA]

The pumps and valves can be activated with the Durametric software or PIWIS, or lacking that be checked using an electrical test tool like the Power Probe; the lines need to be "eyeballed" and checked for cracks or breaks, and should also be blown out with compressed air to check for blockages.

[RdRunner666]

Thanks..... I shall Google some more....

 

-Ryan