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996 tt P0491 & P0492 codes plus ABS/PSM plus 0.5 bar? - Page 1 - 911/Carrera GT - PistonHeads UK

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3 captured repliesPartial discussion capture · Source accounts, not a confirmed diagnosis

THIS DISCUSSION / SOURCE-DERIVED OVERVIEW

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YOUR RESEARCH996 tt P0491 & P0492 codes plus ABS/PSM plus 0.5 bar? - Page 1 - 911/Carrera GT - PistonHeads UK

Leading reported evidence

Set ), if

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
Unplug the MAF (the car will revert to a standard base setting), if that improves it then fit a new MAF.
Original post Read captured discussion
996 tt P0491 & P0492 codes plus ABS/PSM plus 0.5 bar? - Page 1 - 911/Carrera GT - PistonHeads UK

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Leading evidence: 'Set ), if' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Set ), if' (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.

Read captured replies

1 matching discussions · 3 captured posts examined · 1 partial discussions

Frequently discussed actions (1)

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

Set ), if

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
Unplug the MAF (the car will revert to a standard base setting), if that improves it then fit a new MAF.
Original post Read captured discussion
996 tt P0491 & P0492 codes plus ABS/PSM plus 0.5 bar? - Page 1 - 911/Carrera GT - PistonHeads UK

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.

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

PistonHeads: 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: 20261026T124918Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

Hi. I have an 03 996 Turbo that is only boosting to 0.5 bar. The ABS kicks in every now and again for no reason and the ABS/PSM lights show very occasionally. I have read the codes with a fairly basic reader and it showed up the two in the title. No wheel speed sensor codes. Now, could the faults be related? I know MAF's can throw some strange symptoms, (I own Mercedes!!) so I'm after some advice of where to start looking. Thanks

POST 2Original post

Failed MAF will throw up PSM & ABS lights. Unplug the MAF (the car will revert to a standard base setting), if that improves it then fit a new MAF.

POST 3 / ORIGINAL POSTEROriginal post

Will try that, but the lights coming on happens rarely. Idle can be a little lumpy when cold. Could MAF throw the secondary air injection codes?

This is a source reference. Confirm exact model applicability in the original material.