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Error Codes

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3 hours ago, bjf123 said:


My 2006 Boxster with 113,900 miles on it is returning these two error codes. I googled it and see all kinds of conflicting answers. Has anyone run into this? Is it an easy fix?2b0b3db29b707c599678bfb02a8d6891.jpg



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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

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2 minutes ago, bjf123 said:

Thanks. No idea which issue it might be. I’ll have to see which ones I can diagnose on my own. No $$$ at the moment to pay the dealer to look into it.

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Look at the vacuum lines carefully, quite often it is just a small split in one or more lines.

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  • 4 years later...

The high probability fix of the P0491 & P0492 error is to replace the secondary air valve. The valve is prone to fail over time (seize) and not allow the pump to flow air into the exhaust thus causing the P0491 and/or P0492. Use a Durametric or similar on your non-running car, actuate the air pump and check for flow out of the tail pipe. No flow? Blocked secondary air valve.

948 113 203 51 Secondary Air Valve

You must remove the right (pass) side intake and injectors to complete the job so also buy yourself new gaskets for the intake and the injectors for good measure.

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