17 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHMay Have a Dead Cat
Leading reported evidence
Use ones at a salvage yard
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
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Performed · outcome unconfirmed
I found a pair of used ones at a salvage yard and after making sure they were rattle free -- my Boxster converter was bad (and intermittently) because the converter brick was loose -- and nothing came out when I flipped each one around I treated them like glass -- which pretty much describes the bricks -- and paid $450/each and then had them installed.
Leading evidence: 'Use ones at a salvage yard' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Replace converter in my boxster' (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.
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
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Suggestion
FWIW, I lean towards replacing both and have done so when it came time to replace the bad converter in my Boxster.
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.
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Suggestion
If the converter error returns to replace the indicated converter.
Replace indicated sensors, clear the codes, and road
Suggestion or failed attempt
No successful repair reported for this finding.
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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
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Suggestion
The factory guideline is with P0430 (or P0420) to if there are any aging O2 sensor error codes with the converter code to replace the indicated sensors, clear the codes, and road test the car.
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
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Suggestion
The question is do you replace just the "bad" converter or replace both to keep both banks operating under the same conditions as possible?
Replace indicated sensors, clear the codes, and road
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
The factory guideline is with P0430 (or P0420) to if there are any aging O2 sensor error codes with the converter code to replace the indicated sensors, clear the codes, and road test the car.
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
Stock converters with some luck -- and this includes avoiding running over road debris that can bounce up and hit the converter (or the engine!) -- and just normal use can last a long time.)
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
The factory guideline is with P0430 (or P0420) to if there are any aging O2 sensor error codes with the converter code to replace the indicated sensors, clear the codes, and road test the car.
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
Stock converters with some luck -- and this includes avoiding running over road debris that can bounce up and hit the converter (or the engine!) -- and just normal use can last a long time.)
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
I found a pair of used ones at a salvage yard and after making sure they were rattle free -- my Boxster converter was bad (and intermittently) because the converter brick was loose -- and nothing came out when I flipped each one around I treated them like glass -- which pretty much describes the bricks -- and paid $450/each and then had them installed.
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.
17 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: 20261026T122219Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Looking for validation that I haven't missed anything in diagnosing a failed cat. My 03 C2 is up to 86k miles and an increasing amount of track time! Cats are original.
Here goes:
No symptoms, rattles, or "visible" signs of a failure
Filled up with gas this AM and about 2 miles later I throw a CEL
Swing home and plug in the durametric - one code is current - P0430 - cat conv. efficiency bank 2 (no pending codes)
Start logging pre and post cat O2 sensors (car is fully warm, cats are up to temp, etc...)
Bank 1 pre cat voltage varies between .1 and .75, post cat voltage varies between .68 and .71
Bank 2 pre cat voltage varies between .1 and .75, post cat voltage varies between .12 and .69
Looks like my O2 sensors are functioning properly and the bank 2 cat has failed/is failing. Looks like a smoking gun to me...am I missing anything?
The DME has done all the work for you as it monitors the converter performance pretty closely. It uses the #2 (post converter) O2 sensor for this.
That it has flagged the converter is a pretty good sign it is bad.
The factory guideline is with P0430 (or P0420) to if there are any aging O2 sensor error codes with the converter code to replace the indicated sensors, clear the codes, and road test the car. If the converter error returns to replace the indicated converter.
It appears in some way you are lucky in that the converter failure is a hard failure. The #2 sensor reading indicates as much as it is signaling the converter is unable to store oxygen.
The reading normally wants to be -- as you can see from the sensor after the other converter -- around 0.7V.
For reference, a "dead" sensor returns a voltage of 0.45V.
But the very low reading is a sign the converter just can't hold on to oxygen and that's a bad converter.
The question is do you replace just the "bad" converter or replace both to keep both banks operating under the same conditions as possible?
FWIW, I lean towards replacing both and have done so when it came time to replace the bad converter in my Boxster.
Might as well do both. I have my last track event of the season in a few weeks - so will want to figure out my options fast! Looks like there's no real consensus on the best replacement. I'm not really into the price for new OE replacements - time to start researching.
Why is it that wives usually don't approve
or understand why this might be a good upgrade?
Did you acquire 200 cell cats SP? Do you have any track videos to share?
Steve, I do have 200 cell cats and love the sound with the FisterD's. Don't any vids from this year but maybe in a few weeks. Mr. Spruden and I will be at the same event.
OE converter replacements are expensive. At my local dealer a year or so ago I was quoted around $1000/manifold for new converters and this with some dealer parts department goodwill. 996 converters I would be (almost) willing to bet even more costly.
I found a pair of used ones at a salvage yard and after making sure they were rattle free -- my Boxster converter was bad (and intermittently) because the converter brick was loose -- and nothing came out when I flipped each one around I treated them like glass -- which pretty much describes the bricks -- and paid $450/each and then had them installed.
Might add if you track your car you have to budget for more frequent converter replacement. The hard track use with the increase in temperature is really hard on the converters. (While one converter was bad -- due to a loose brick -- the other converter was just fine and at that time the car had covered around 275K miles. Stock converters with some luck -- and this includes avoiding running over road debris that can bounce up and hit the converter (or the engine!) -- and just normal use can last a long time.)
Before pulling the trigger on new cats I decided to do one more round of diagnosis.
I swapped the bank 1 and bank 2 post cat O2 sensors, cleared the CEL and went on a drive to get the car up to operating temperature. The O2 voltage readings were exactly the same as before. Bank 1 pre-cat fluctuation and post-cat solid around .7v. Bank 2 fluctuation both pre and post-cat.
Both O2 sensors looked identical - no obvious differences in appearance from the "business end" of the sensor when comparing bank 1 to bank 2. Looks like the cat is failing and a replacement is in order.
I figure while I'm spending money - I should plan on O2 sensors all around (maybe not right away) and have looked at the
Bosch parts site
but there are several part numbers listed for both downstream and upstream. Does anyone know which ones are correct?
Spruden, the P04020/0430 codes are quite accurate in terms of tracking the cats' efficiency and if it was one of the sensors, the DME would have flagged that instead. One exception I found is if your cat insert is dislodged inside but it's still good, that could also trip the P0420/0430. The reason is once the insert starts to knock around, it can hit the tip of the post-cat O2 sensor blocking the air flow.
So I would suggest you remove the bank 2 cat and inspect it visually and shake it and see if anything is loose inside. Remove the post-cat sensor so you can peek at the inside. If your post-cat sensor tip is very shiny, your insert is knocking on it.
Get the Bosch 16433 precat and 16435 postcat from Amazon. Best price and quality.
All good points and I agree - those codes seem very accurate as the comparison for the DME between pre and post cat 02 sensors is very binary. It's either working or it isn't.
I did remove the post-cat sensors on both banks - they are not shiny and there's no sign of anything loose inside of the offending cat. I've ordered the 200 cell x pipe cats from FVD and they should arrive mid-next week. They seemed to be well made, and relatively affordable with the great RL discount.
Will update the thread with impressions once I get to installing them.
Also - thanks for the Bosch part numbers...will get those in process as well (although all indications are that my sensors are working). Last thing - talk about an easy job to troubleshoot - I wish all O2 sensors were this easy to get to.
This is a source reference. Confirm exact model applicability in the original material.
