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Error code: P0491 / P0492

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9 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW

Discussion summary

YOUR RESEARCHError code: P0491 / P0492

Leading reported evidence

Replace check valve

Suggestion or failed attempt

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

Thanks again Ahsai, do I need to remove the intake manifold to change the check valve ?

Original post Read captured discussion
Error code: P0491 / P0492
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Leading evidence: 'Replace check valve' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Replace check valve' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.

Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.

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1 matching discussions · 9 captured posts examined · 0 partial discussions

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Replace following 3 parts

Suggestion or failed attempt

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context

Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

I have the error code: P0491 / P0492 on my 996C4S, I have follow some guide lines here to change the following 3 parts:

Original post Read captured discussion
Error code: P0491 / P0492
Frequently discussed actions (2)

These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.

Replace check valve

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

Thanks again Ahsai, do I need to remove the intake manifold to change the check valve ?

Original post Read captured discussion
Error code: P0491 / P0492

Replace following 3 parts

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

I have the error code: P0491 / P0492 on my 996C4S, I have follow some guide lines here to change the following 3 parts:

Original post Read captured discussion
Error code: P0491 / P0492
Coverage and how to read this overview

Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.

9 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.

  • Rennlist: 1 discussions

0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.

0 acknowledgements have no verified action link; they do not establish a repair result.

Generation: 20261027T150039Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

Hi everyone, I have the error code: P0491 / P0492 on my 996C4S, I have follow some guide lines here to change the following 3 parts: 993.113.245.01 M96.20 (996.113.249.01) Air pump control/shut-off valve 996.605.123.01 Change-over valve However, I am unable to locate where is this part on the car (attached photo)? 993.113.250.03 M96.20 Secondary air injection check valve. Would appreciate if anyone can advise where is the part located on the car? A photo where the part is on the car will be really helpful. I have the 996 parts diagram, but the diagram doesn't show where is the part. Thank you & have a great day !

POST 2Original post

Those two mechanical valves are combined into a single valve 99711324990.

POST 3 / ORIGINAL POSTEROriginal post

Thank you Ahsai, Do you know where is the part located on the engine ? I am unable to find it .

POST 4Original post

You need to remove the alternator to see it. Deep in the engine right behind the alternator. You will see a plastic vacuum canister also behind the combo valve.

POST 5Original post

See post #13 here on a Boxter. Same for your engine. http://986forum.com/forums/general-d...off-valve.html

POST 6 / ORIGINAL POSTEROriginal post

Thanks again Ahsai, do I need to remove the intake manifold to change the check valve ? I removed the alternator but did not see the valve.

POST 7Original post

Look at about one foot behind the back of the alternator, you should see a silver valve and a black plastic canister. I've never replaced that valve but I would expect you need to remove at least the T plenum if not the left intake manifold as well.

POST 8 / ORIGINAL POSTEROriginal post

Thank you very much, I will try to fond it again.

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