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YOUR RESEARCHCatalytic Converter Efficiency Codes - Swapped sides after plug change
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Replace air filter a few weekends ago)
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Performed · outcome unconfirmed · Original poster
I did clean my MAF today (replaced air filter a few weekends ago).
Catalytic Converter Efficiency Codes - Swapped sides after plug change
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Leading evidence: 'Replace air filter a few weekends ago)' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Clean maf today (' (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.
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Suggestion · Original poster
I did clean my MAF today (replaced air filter a few weekends ago).
Catalytic Converter Efficiency Codes - Swapped sides after plug change
Replace driver side cat only
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Suggestion · Original poster
I had been planning on replacing my driver side cat only, but now that the other side has thrown the code as well, it means I either have two bad cats, or there may be something else at play that I conjured up during my spark plug replacements.
Catalytic Converter Efficiency Codes - Swapped sides after plug change
Reset code
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Catalytic Converter Efficiency Codes - Swapped sides after plug change
Run cat efficiency
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Suggestion
Since the car doesn't run the cat efficiency test everytime you drive it and you need two consecutive failures to trip the CEL, when the cats are marginal the CEL will appear to be random.
Catalytic Converter Efficiency Codes - Swapped sides after plug change
Replace driver side cat only
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Suggestion · Original poster
I had been planning on replacing my driver side cat only, but now that the other side has thrown the code as well, it means I either have two bad cats, or there may be something else at play that I conjured up during my spark plug replacements.
Catalytic Converter Efficiency Codes - Swapped sides after plug change
Run cat efficiency
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Suggestion
Since the car doesn't run the cat efficiency test everytime you drive it and you need two consecutive failures to trip the CEL, when the cats are marginal the CEL will appear to be random.
Catalytic Converter Efficiency Codes - Swapped sides after plug change
Run with the most likely scenario
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Suggestion · Original poster
Given those symptoms, any ideas whether there may be something else going on, or should I run with the most likely scenario, which is that I probably have two failing catalytic converters?
Catalytic Converter Efficiency Codes - Swapped sides after plug change
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4 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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Generation: 20261026T161109Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Hi All,
I did my plug replacement a couple weekends ago, and everything went well. Before the plug change, I had been getting the occasional P0420 error (Catalytic Converter efficiency below threshold (or something like that)) on Bank 1 (driver side). After the plug swap, I didn't get any codes for a week, and now this past weekend, I've gotten two P0430 codes and CEL's, which is the same error, but for the passenger side (Bank 2). No P0420's have reoccured yet.
I had been planning on replacing my driver side cat only, but now that the other side has thrown the code as well, it means I either have two bad cats, or there may be something else at play that I conjured up during my spark plug replacements.
Given those symptoms, any ideas whether there may be something else going on, or should I run with the most likely scenario, which is that I probably have two failing catalytic converters? I did clean my MAF today (replaced air filter a few weekends ago). Maybe that will help?
On a side note, I did reach out to Gert @ Carnewal.com, and he has a great deal on refreshed catalytic converters that I'm very likely to pull the trigger on if I need to do both cat's. I'm just trying to work out the logistics since it involves sending my current cats to him first. (Car is my daily driver).
Any thoughts on the above symptoms? Thanks in advance.
-Don
Do you have a scanner that can read the O2 sensor voltage in real-time? E.g., Durametric or OBDII Android Torque app? See post #8 here
https://rennlist.com/forums/996-foru...l#post10967076
The readings will tell you how healthy your cats are. From what you described, it does sound like your cats are failing.
I have the 200 cell cats from Gert. I love them and there's no CEL. The sound is sublime with my Fister cans. Gert is just a great guy and a pleasure to do business with. I'm gonna do my first smog on theses cats in the coming weeks.
Btw, I don't think the codes have anything to do with the new plugs and MAF. Since the car doesn't run the cat efficiency test everytime you drive it and you need two consecutive failures to trip the CEL, when the cats are marginal the CEL will appear to be random. Sometimes they pass and sometimes they fail.
You need a durametric. I got that code for one cat and reset the code. That was over a year ago and it still hasn't come back. You cats maybe failing, but it sounds like the are failing slowly.
The only way to know for sure is to reset and see if it throws the code again. Unless you took you exhaust down to change the plugs I don't see any correlation between the two events.
I am sorry to hear that Gert's relatively inexpensive cat fix (with the 200 cell cats) requires you to send your cats to him first. I have no problem sending mine as a core but having to send mine and then wait for him to do the work and send them back adds to the opportunity cost.
This is a source reference. Confirm exact model applicability in the original material.
