29 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHAlternatives?? P0430 / P0420
Leading reported evidence
Clean maf and never had another code
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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Discussions that performed work without a confirmed outcome
1
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Leading evidence: 'Clean maf and never had another code' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check around ebay and also fabspeed' (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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1
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Performed · outcome unconfirmed
Upstream sensors replaced, downstream are OEM still.
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Discussions that performed work without a confirmed outcome
1
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Performed · outcome unconfirmed
May 2021: New Spark Plugs (coils were replaced a year earlier)
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Discussions that performed work without a confirmed outcome
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Performed · outcome unconfirmed
2) Factory, used=cheaper, but unknown history makes me wary
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Performed · outcome unconfirmed
The requirements also sunset provisions allowing the sale of certified used catalytic converters beginning July 10, 2008.
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Suggestion
Next up, O2 sensors (I would have said check for physical damage, but it's on both sides so prolly not.) I would assume for $2k your mechanic is doing all of this and more.
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Suggestion
My thoughts from here are: AOS was crap out of the box and needs to be replaced, switch downstream sensors, replace the MAF to eliminate the possibility, test the coolant system, test for an exhaust system leak somewhere?
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.
29 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.
1 acknowledgements have no verified action link; they do not establish a repair result.
Outcome without a verified action link
September 2021: Try to smog again and the Cats are still not ready for testing per the shop's reader.
Well, the car has been running great and with summer coming began looking into a paint job
Then, yesterday the demon "
check
engine
" light comes on
I take the car to my mechanic and he puts it on the thingy and up pops these two codes. Catalytic Converter
Called parts and the cost is
$2000
Do I have any alternatives/choices
You must be mistaken sir, these cars are cheap to maintain.
But seriously, are cats breaking apart, failing from oil contamination, what? There are many aftermarket alternantives.
P.S. buy a code reader/clearer.
Hang on there cowboy, cats fail for a reason! First, clear the codes. You can pretty much drive on failed cats, well, forever ... depending on how they failed. If the exhaust pressure is anywhere near nominal your good to go. The most common way of killing your converters is running raw gasoline thru the exhaust. Do you recall anything weird happening with your fuel management (plugs, evaporator, tank overfilled, that-sort-of-thing)? That needs to be fixed or you will just kill another set of cats. Next up, O2 sensors (I would have said check for physical damage, but it's on both sides so prolly not.) I would assume for $2k your mechanic is doing all of this and more. I would hope much more.
He gave me a quote just for the cats is $2K. Since two codes popped up,
P
0430
and
P0420
, both are bad
I'm gonna check around ebay and also Fabspeed. Thanks
It seems unlikely for both cats to go bad at the same time. When I get codes pointing to both sides of the engine I tend to look up stream for the problem. Take a look at the voltage traces from the oxygen sensors (before and after) the cats to see what's going on. Ideally the sensors before the cats are sinusoidal and the readings after the cats are pretty flat. If you see no voltage you could just have a bad sensor. If you see sinusoidal waves after the cats that are off set from the upstream sensors it suggests bad cats. I chased a problem like this on a 4runner one time. I changed both sensors and was just about to change the cat when i realized a bad MAF would cause both sides to appear off at the same time. I cleaned the MAF and never had another code...
The factory guidelines state that if either or both of the above codes are accompanied by O2 sensor codes to replace the sensors indicated, clear the error codes, then road test the car.
If the converter error codes come on again replace the converters.
I've been dealing with an intermittent P0430 for years now in my 02 Boxster. I found switching to a top tier gasoline (mostly Shell but Chevron other brands work too) help keep the CEL dark.
Gotta agree with Uber two bad cats at the same time would be odd without a drivability problem, unless you have been driving with the MIL lamp on for 6 months. Just because you have a cat efficiency code does not automatically point to the cats. If the cats are bad the O2 sensor wave forms on O2's after the cats will mimic the ones before the cats.
A cat that is up to temperature has very little oxygen coming out of it, therefor the sensor pattern will be relatively flat compared to the one in front of the cat. I suspect that something else triggered it. You also need to know what the short and long term fuel trims are, if they are normal clear the codes and drive it until it reruns the monitor. If no code reappears you are good to go.
I had a P0420 a month ago. Swapped the rear O2 sensors side to side to figure out if it was a bad cat or sensor and I haven't had a check engine light since...maybe had a bad connection or bad gas I'd guess.
I'm taking the car into the mechanic on Tuesday to follow through on some of the suggestions on this board. I will post the final results. Thanks everybody
RL'ers are the best
Ha the same cat code pop up on me (both at the same time) last week; I find the premise that both cat converters failed at the same time suspect at best. I've reset them and waiting to see if they come back, odds are there was somethign in the gas.
I got the P0420 again, so I need a new bank 1 cat. It took several hundred miles for the check engine light to come back on. Anyone got a low mileage one sitting around?
Isn't there a law here in California prohibiting the sale of used CC
I called a local Porsche parts recycler and that is what they told me. This is so frustrating
I think I may have a cat on it's way out as well. I've looked into a few options:
1) Factory, new=expensive and no performance gain
2) Factory, used=cheaper, but unknown history makes me wary
3) Aftermarket full system=less expensive than factory new (although not cheap), and performance gain
4) Aftermarket weld in cat=least expensive option, potential small performance gain
I'm considering #4.
http://www.hjsna.com/porsche-catalytic-converter/
At least you have 2 more options than us in CA. Are there any aftermarket cats CARB approved? I can't find any and I don't want the headache (having been there with other cars)
News to me used cats can't be sold. However, I've never tried to buy one.
Call or email Parts Heaven in Hayward CA and ask if it has any used converters for sale for your CA car.
I just popped for 200 cell X cats from a place in Canada. Had 0430. Decent price, for cats that is. No tax either. And you don't need X pipe. A lot less for crossovers.
Information About New Regulations for Aftermarket Catalytic Converters
The ARB adopted revised regulations and evaluation procedures in October 2007 for the approval of new aftermarket catalytic converters sold in California. The requirements apply to all new aftermarket converters produced for sale or sold in California after January 1, 2009. The requirements also sunset provisions allowing the sale of certified used catalytic converters beginning July 10, 2008. This means that no used converter can be legally advertised for sale, sold, or installed in California after this date.
http://www.arb.ca.gov/msprog/aftermk...ftermktcat.htm
morgana
Got NHP cats marketed/made (?) by Maxspeed. They are less than Fab but who knows about any reliability tradeoffs. I expect them not to last as long as OEM, but then those only lasted for 60K. I track the car mostly and have been getting codes for #6 misfire, inefficient cats + low on power at high rpms. Couldn't pass smog here in CA without getting it done in a 20 mile window. Lucky there was a window at all.
Maxspeed was sold out of the X-pipe, so I figure they sell a lot to customers who could otherwise be pretty pissed if they were crap. They are on eBay, but I called them (Maxspeed) direct. They had a cancellation I then bought. More coming shortly. Gent said they sell mostly in CA, so the CEL would be a show stopper here come registration time. Probably true of most states. Reviews look pretty good mostly. Proof's in the pudding, though.
Does this still occur or did you solve with new sensors/90 degree bends? I ask because I am just starting to notice this same pattern after installing my FabSpeed 200 cel cats. Ive only had the codes twice, once immediately after install and again some 300 miles later after a fill up. Thanks.
Carnewal 200 cells
You can send in your own cats, if you want to save money, he opens them up and put 200 cells elements.
Awesome work and you keep the factory look.
I've joined this mystery affliction and damn is it frustrating because there is no straight ahead cure to this CEL remedy and I've got my back up against the wall with my smog/registration deadline.
Here is my path on my 2004 40th Anniversary 911 of unsuccessfully dealing with these crap codes:
October 2020: Install Magnaflow Cats 43K miles (CARB approved, old cats were 17 years old with low-ish mileage but started hearing a rattle and didn't want to start a wildfire driving through the country). Upstream sensors replaced, downstream are OEM still.
October 2020: Install IMS bearing retrofit, New Air/Oil Separator, new Rear Main Seal (all preventative maintenance)
May 2021: Clean MAF (now at 50k miles)
May 2021: Oil & Filter Change, liquimolly engine cleaner fuel additive utilized
May 2021: New Spark Plugs (coils were replaced a year earlier)
June 2021: Error Code 420. Reset, came back on after 300 miles.
August 2021: Needed to renew my registration and get a smog test. Attempt to put into test mode and follow the instructions for Porsche 996 (idle for 2 minutes, 10 minutes below 30mph, 20 minutes at 40-60mph all while going under 3k holy sh*t does this process suck if you live in a city) car pops code in the driveway of the smog shop. FML.
August 2021: Switch sensors from left to right to see if the code fault follows and I can determine it's a crap sensor, it does but it pulls a P0420 and now a P0430 this time around. Reset error code and drive 300 miles
September 2021: Try to smog again and the Cats are still not ready for testing per the shop's reader. I'm on extended registration, met with California BAR to ensure them that the car comes with 2 cats not 4 like their website states after nearly getting into fisticuffs with SMOG operators who accuse me of ripping out 2 cats because the smog shop pulls up the government website that says the car has 4 cats. Been on the phone with Magnaflow (very nice people) 4+ times and have had 4 trips to the smog shop.
Note: if I let the car sit for a week I get some white smoke briefly upon start up. If I drive it frequently, doesn't happen.
My thoughts from here are: AOS was crap out of the box and needs to be replaced, switch downstream sensors, replace the MAF to eliminate the possibility, test the coolant system, test for an exhaust system leak somewhere? All these guesses $uck.
In the Bay Area, if anyone has a line on a guru to help me find enlightenment on this issue I'd be very thankful.
FML
