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Fault code- help requested

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

THIS DISCUSSION / SOURCE-DERIVED OVERVIEW

Discussion summary

YOUR RESEARCHFault code- help requested

Leading reported evidence

Replace on the other side

Performed · outcome unconfirmed

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 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
It is an '02 and I already had the cataytic converter replaced on the other side.
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Fault code- help requested

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Leading evidence: 'Replace on the other side' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Replace on the other side' (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 · 8 captured posts examined · 0 partial discussions

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Replace under warranty

Performed · outcome unconfirmed

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
Brought vehicle to dealer and they confirmed a bad catalytic converter which will be replaced under warranty.
Original post Read captured discussion
Fault code- help requested

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 on the other side

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
It is an '02 and I already had the cataytic converter replaced on the other side.
Original post Read captured discussion
Fault code- help requested

Replace under warranty

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
Brought vehicle to dealer and they confirmed a bad catalytic converter which will be replaced under warranty.
Original post Read captured discussion
Fault code- help requested

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.

8 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: 20261027T053112Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

My cel came on and I read the fault code. It is PO420, TWC Conversion bank one above limit. Does anyone know what that means? TIA, much appreciated.

POST 2Original post

Possible fault causes - Oxygen sensor ahead of and after TWC exchanged - Valve lift fault - Aged oxygen sensor after TWC - TWC faulty TWC = Three way catalytic convertor Did the CEL come on during a cold start by any chance?

POST 3Original post

what year is the car?

POST 4 / ORIGINAL POSTEROriginal post

Thanks guys. It is an '02 and I already had the cataytic converter replaced on the other side. Also I noticed an exhaust rattle so my bet is the other cat needs replacement. So even though I am out of warranty for everything else if the cats are still covered I will go back to the dealer. I'll let you know but that's my bet.

POST 5Original post

8 YEAR 80K MILE WARRENTY ON THE DME AND CATS

POST 6 / ORIGINAL POSTEROriginal post

Most excellent Brad!!

POST 7 / ORIGINAL POSTEROriginal post

Just wanted to complete this thread. Brought vehicle to dealer and they confirmed a bad catalytic converter which will be replaced under warranty.

POST 8Original post

Wooooo Hooooooooo! Love it when a plan comes together Glad the fix was FOC

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