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p0300 only code - 986 Forum - The Community for Porsche Boxster & Cayman Owners

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Original source

5 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis

THIS DISCUSSION / SOURCE-DERIVED OVERVIEW

Discussion summary

YOUR RESEARCHp0300 only code - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Leading reported evidence

Replace cap, cel shut off

Performed · outcome unconfirmed

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 performed work without a confirmed outcome: 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.

Performed · outcome unconfirmed · Original poster
Replaced the cap, CEL shut off.
Original post Read captured discussion
p0300 only code - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Frequently discussed work

Check ignition coils

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
check coils for splits/cracks and plugs for fouling.
Original post Read captured discussion
p0300 only code - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Read full discussion summary

Leading evidence: 'Replace cap, cel shut off' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check ignition coils' (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 · 5 captured posts examined · 0 partial discussions

Compare 2 other evidence results

Check ignition coils

Suggestion or failed attempt

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
check coils for splits/cracks and plugs for fouling.
Original post Read captured discussion
p0300 only code - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Check moisture over the coolant cap

Suggestion or failed attempt

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
Now, pop the trunk & check for moisture over the coolant cap.
Original post Read captured discussion
p0300 only code - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Frequently discussed actions (3)

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

Check ignition coils

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
check coils for splits/cracks and plugs for fouling.
Original post Read captured discussion
p0300 only code - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Check moisture over the coolant cap

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
Now, pop the trunk & check for moisture over the coolant cap.
Original post Read captured discussion
p0300 only code - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Replace cap, cel shut off

No successful repair reported for this finding.

0
Reported fixes: 0
Unsuccessful attempts: 1
Discussions

Read evidence and context

Discussions that performed work without a confirmed outcome: 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.

Performed · outcome unconfirmed · Original poster
Replaced the cap, CEL shut off.
Original post Read captured discussion
p0300 only code - 986 Forum - The Community for Porsche Boxster & Cayman Owners

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.

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

986Forum: 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: 20261027T042512Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

CEL came on. Went to advanced auto and had them scan it (only place open on Easter) and they are telling me that only this code is coming up. Any idea what this could be?

POST 2Original post

Googled it, Misfire code... check coils for splits/cracks and plugs for fouling. Could also be dirty fuel filter.

POST 3Original post

Failing AOS, dirty MAF sensor, dirty fuel injectors and what Steve posted.

POST 4 / ORIGINAL POSTEROriginal post

Turns out the seal for the gas cap was dried out and cracking. Replaced the cap, CEL shut off.

POST 5Original post

Quotes source post: 443667

Now, pop the trunk & check for moisture over the coolant cap. make sure that is the latest version.

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