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Audi A4 The Audi A4 model offers nimble handling and performance that makes it one of the leading cars in its class. Read more about the Audi A4 in the Audi A4 review.

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Old 07-21-2007, 02:43 PM
1st Gear
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Default P0491 and P0492??

Got these codes saying Secondary Air System bak 1 and bank 2? What could this be? I had them reset and the CEL hasn't come back on yet....?
Tim Olson
Old 07-22-2007, 12:17 AM
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Default RE: P0491 and P0492??

Bentley Publishers doesn't list those codes. Lets hope they
don't return.
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Old 07-22-2007, 09:07 AM
1st Gear
Join Date: Jun 2006
Posts: 434
Default RE: P0491 and P0492??

could be a combi valve or the vacuum lines to the valves. Do you hear the pump running after start up(sounds like a hair dryer). If the engine is already hot enough though you will not hear it run
Old 07-22-2007, 12:11 PM
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Default RE: P0491 and P0492??

This is a picture of the secondary air injection pump. You might want to check the hoses for any leaks.

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Old 07-22-2007, 12:11 PM

01, 0491, 0492, 2000, 2001, 2004, 42, a4, a6, air, audi, code, injection, kombi, p0491, p0492, secondary, system, trouble

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