+1, what you describe is very unlikely............... *NM*

So, I just got off the phone with my local dealer. I took my '02 in this morning because the check engine light came on (note that it seems to be driving fine). The first thing he says is "hold on a minute while I add this up." My heart stops. He says the light means I have to replace 2 catalytic converters plus related stuff for a total of $3200. I laughed hysterically. After recovering my breath I am not sure what to do beyond taking it to an independent for verification. Any advice?

... it's very unlikely that the cats are bad all of the sudden.
I'd get a 2nd opinion.
There are a zillion things that can trigger a CEL, most of them easily and cheaply repairable.
Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna




Edited 1 time(s). Last edit at 12/21/2010 08:00AM by Pedro (Weston, FL). (view changes)

“Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein

weak you may not need to replace them right away. I have 'nursed' one 'weak' converter -- it generates a P0430 error code once in awhile -- on my 02 Boxster for years now even getting my car through CA smog checks with flying colors (well, passing colors (numbers) anyhow).

Now if one converter really truly bad bad enough to require replacement to alleviate drivability problems, to bring the car into emissions compliance, etc. an argument could be made to replace both converters.

But first what were the error codes?

Sincerely,

MarcW.

You are faced with a bill for $3+K. Which means spending $40-70 on a code reader to get the exact codes is what I call a noise level expense. Actron is a typical brand.

Reading codes is trivial, plug the gadget in by your left knee and push the on button and read the screen basically.

Once you have the code(s), post them here and people who have the factory manuals will be glad to list the possible causes and suggest a low cost approach you can consider. At least then if you go to an independent, you'll be armed with some knowledge and can speak with the mechanic intelligently.

Even post your location and someone may know of a mechanic nearby you can trust.

I'm not saying it couldn't be, just I'd not think it likely you'd need cats.

Thanks for your comments folks, I appreciate it. Your thoughts match my intuition, and tomorrow I am taking it to an independent. Unless the independent verifies the diagnosis, I'm through with this dealer after 5+ years of being a customer as this is the second bad experience I've had with them in a row.

I didn't ask for the codes, but I will tomorrow when I pick up the car. I will post them here and would be very grateful for your continued advice on the matter.

I am in Ashburn VA, so you might guess the dealer. Recommendations for independents are welcome -- as of now I will likely head to Curry's.

As I used to go there too.

[sites.google.com] is a list several years old but you might check the Chantilly location out by phone or with some fellow P-car folk. I found my indie by just visiting and wandering around and talking to the mechanic...which I like do do removing the write-up filter between owner and the guy who really knows what he found in your car.

Quote
jeff in VA
So, I just got off the phone with my local dealer. I took my '02 in this morning because the check engine light came on (note that it seems to be driving fine). The first thing he says is "hold on a minute while I add this up." My heart stops. He says the light means I have to replace 2 catalytic converters plus related stuff for a total of $3200. I laughed hysterically. After recovering my breath I am not sure what to do beyond taking it to an independent for verification. Any advice?

The "joke" might be on the dealer... Catalytic converters, which are considered "major emission control components" are covered by a federal warranty for the first 8 years or 80,000 miles after a vehicle is put into service, whichever comes first.

So, depending on when your car was first put in service (and how much mileage is on it), you may be able to go back to that dealer and now tell him that you wanted to make sure that he understood why you were laughing hysterically! LOL!!!

I just helped my next door neighbor have his cat replaced on his Toyota Matrix. He just went in there (at 78K miles), armed with a copy of the statute, and he said he had never seen them be that accommodating! That law is ironclad and they know not to mess with it because it exposes them to MAJOR fines.

Regards, Maurice.

Jeff
What is the mileage on your 02?

Joe

I'm over 100k, so that wont work for me. ;-(

Bad 02 sensors (which are a much more common issue on the 986) can cause a cat failure code.

Curry's is good - I have always had good experience with them.

Also, check out Intersport in Tyson's - they aren't cheap but Charlie and Omar are good guys and the KNOW Porsches (you should see some of the hardware sitting in their lot!)

Finally, if the cats really are bad, check your county emissions regulations - some of the VA counties DO NOT REQUIRE an emissions check, so you could just ditch the cats.

1998 986 Turbo-Look Cab
172,000 Miles
Dilithium Crystal Supercharger

Since you are close by give Ivan a call at IMA Motorsports. They are located behind the Cadillac dealer on Rt. 50 just east of South Riding.
I've had a bunch of work done there and have always been treated right.

Thanks for the recommendation. I have heard good things about IMA Motorsports. I will try them next, if it doesn't work out at Curry's.

Ok, so here's the scoop. The problem code was P0430. The dealer said this meant that I would need to replace both cats and, if that didn't solve the issue, the O2 sensor(s).

I took the car to Currys, a local independent. They listened to my story and then spent some time with the car. Based on the fact that the fault code has only been triggered once in the life of the car, and that it has not reoccurred for 3 drive cycles, they did not think it was the cats. He said he noticed some oil leakage around the spark plug tube seats and hypothesized that some oil got into the tube and blown onto the cats, causing a moment of poor performance and the fault code. He cleared the codes and suggested I run a couple of tanks of gas through the car and see if the code triggers again before I do anything more. He also suggested I change out the spark plugs and spark plug tubes for ~$750 to fix what he thinks is a leak in the area of the spark plug tube.

The Curry's story sounds a lot more likely to me, as I do recall now that I had a bit of oil smoke on start-up prior to the CEL light. So maybe it is a bit of oil in the spark plug tube.

What do you folks think?

... oil to the outside of the engine, not into the cats if the tubes crack or the O-Rings are damaged, but I highly doubt that they caused your error code.
If you had an excessive amount of oil into the cats it's easily determined by inspecting the throttle body and air intake plenums for evidence of engine oil.
This is a fairly common occurrence, generally due to the failure of the Air/Oil Separator.
That's the first place I'd inspect if it were my car.
Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

for some misdiagnosed spark plug tube o-ring leaks when the problem is a loose or leaking gas cap or an oil filler tube cap, or anyone of a number of things.

Sincerely,

MarcW.



Edited 1 time(s). Last edit at 12/21/2010 09:31PM by MarcW. (view changes)

The only error code was P0430.

off and on. Warm weather using Shell gas not very often, maybe months between the CEL and error code.

Cold weather and Rotten Robbie or USA gas (cause this gas sometimes considerably cheaper than Shell/Chevron gas where I live) the CEL comes on more often.

The Porsche manual states (paraphrasing) that if the P0430 (bank #2 converter performing below effficient threshold; P0420 is the other bank, #1) is not accompanied by one or more aging O2 sensor codes to replace the converter.

If the aging O2 sensor codes are read out to replace the sensors, clear the colds, and test drive the car. If the P0430 (or P0420) error pops up, replace the converter(s).

Absent any driveability issues (and my Boxster has never exhibiting/manifested any at any time before during or after the P0430 CEL appeared) I'd say buy a cheap code reader/clearer and use it whenever you get tired of the light being on.

If you want to get a bit more fancy, run a bottle or two of Techron through the car, following instructions on the bottle to clean out the fuel system (including injectors), remove valve and combustion chamber deposits and remove O2 sensor and even converter deposits. If the spark plugs are old you might consider having these replaced as well.

Doing the above might (might) be a fountain of youth for the converters in that the engine runs better and because of this the converters have less work to do.

The converters store oxygen (removing it from the oxygen in the exhaust gases on a lean (excessive oxygen) cycle and release it to process exhaust gases on a rich (less oxygen) cycle. The engine controller constantly varies the fuel:air mixture from slightly lean to slightly rich (on either side of ideal as far as the converters are concerned) and thus each cylinder (bank actually) cycles between a bit of excess oxygen in the exhaust gases (which the converters remove cause they attract oxygen) to a bit too little oxygen in the exhaust gases which during this time the converters give up their stored oxygen in the chemical process that converters more harmful exhaust gases into less harmful gases.

Anyhow, this P0430 error code essentially tells you the converter is not able to store as much oxygen it needs. Now you can't increase its oxygen storing capacity (short of replating its interior with the catalytic metals). The use of Techron (mentioned above) may help by removing some deposits in the converter that prevent oxygen from being retained by the catalyst metals and these same deposits that interfere with the interaction of the exhaust gases with the catalyst metals.

Along with this if this Techron clean's up combustion this works to reduce the amount of harmful exhaust gases in the exhaust that are processed by the covnerters. The converter's oxygen budget is increased due to less demand on its oxygen storage capacity.

I would not replace a converter just yet.

If the spark plug tubes are leaking I'd get those taken care of.

Sincerely,

MarcW.

Marc, your advice is actually pretty consistent with what the Curry's tech told me. He also suggested running a bottle of Techron through the system along with a couple of tanks of Shell gas to try to clean up stuff as best as possible before doing anything dramatic. And, because of issues around the spark plug tubes, he suggested changing the spark plugs too. Looking at my service intervals, it looks like I'm about due to change them anyway, so I am going to get that done.

Pedro and Red_Lightning suggested I look at the AOS too, so I will ask about that when I go in for the new spark plugs. Is there a separate error code for the AOS?

As for Intersport -- if Curry's lets me down on this, then they are next on my list of independents. Thanks for the recommendation.

It sure is nice having a place to ask questions of knowledgeable people that don't have a financial interest in the answers. Thanks again everyone for all your help.

other owners reporting AOS failures here (and elsewhere) and not AFAIK (and remember) not one AOS failure resulted in either a P0430 or P0420 error code.

When my Boxster's first AOS was acting up -- at that time I didn't realize it was the AOS -- there were no error codes. Probably cause I didn't run the engine long enough to allow the Ecu to set any error code.
There were other symptoms to be sure.

As the 2nd AOS was going bad -- again I didn't realize that it was going bad -- there were error codes that were related to the Ecu reaching its rich adaptation limit. I suspected a MAF problem and decided to continue to drive the car -- I was on a cross country road trip and was nearly 1K miles from 'home'.

After 2 days the 3rd day the AOS made its condition known by upon cold engine start the engine emitting billowing clouds of oil smoke.

Based on what you have posted I don't suspect the AOS is acting up but it never hurts to be sure it is *not* acting up. I know with the P0430 error code my Boxster's engine has never exhibited any signs of any trouble at all at any time. The CEL would come on and that was the only way -- after I read the codes of course -- I knew it was due to P0430.

My experience with 2 AOS's going bad in my 02 Boxster is the various symptoms can be: a mildly hunting idle; a bit of hesitation off idle; rough idle; consistent persistent smoking (oil smoke) from the tailpipe; oil dripping from the tailpipe; rapid oil consumption; with the engine idling being unable to remove the oil tube filler cap from the oil tube against the huge pressure difference inside the crankcase and outside the crankcase due to the AOS permitting full engine vacuum (at idle) to be applied to the engine crankcase). Others have reported hearing noises from air being drawn into the engine around the engine seals (RMS or the one at the front of the engine or even through a crack in the oil filler tube). Another symptom or sign of AOS troubles is upon removal of the throttle body finding the inside of the TB wet with oil or even (as I found) the butterfly wet enough with oil that an oil drop was hanging from the bottom of the butterfly valve. Oil at the hose connection just downstream (closer to the engine's intake valves) of the throttle body. This hose connection is where the AOS connects to the intake system and where air from the crankcase after being passed through the AOS (to remove oil vapor) is fed into the engine's intake system where it will be burned. And of course P1128/P1130 (IIRC) error codes. There might be other symptoms but I think the above includes most of them.

As always I like to stress that if the AOS is suspected to avoid starting the engine and to avoid driving the car until you can have the AOS eliminated as the cause of whatever behavior/symptoms you are seeing/experiencing. Or if the AOS is identified as the cause having it replaced. IOWs, fix the AOS first (if it needs fixing) then worry about other things like well just for example leaking spark plug tubes or a possibly bad converter.

Sincerely,

MarcW.

what the techs at the shop you took the car too said I believe you have a pretty good shop to take the car to. I mean there are times when a $3K repair is justified. But one certainly wants enough info and discussion from the tech recommending this action to have sufficient confidence (approx. $3K worth...) this expenditure will have the car back in tip top shape.

Also, though there are times when a less drastic course of action is called for and a wait and see attitude is appropriate as long in the tech's opinion the car is not at further risk to serious damage. For instance I would be willing to drop the hammer on a new AOS before giving the suspected failing AOS enough time to manifest all the possible symptoms of failure to avoid the risk to the engine letting the AOS develop into a full blown with no doubt at all AOS failure.

Sincerely,

MarcW.

And get the proper tool for removing the O2 sensors. A spanner will just round the O2 sensor housing and you will smash you knuckles into something hard..

I know this is an old thread. I am getting p0430. My O2 Sensors pass the the IM test, but getting the po430 code. I have replaced the plug tubes, and AOS because I was getting oil leaks and some smoke, which have now cleared up, but the code still shows.

In graphing the o2 sensors voltages, I get wide variations on the pre cat sensors and fairly flat on the post o2 cat sensors.
So I believe that is telling me that my O2 sensors are working and my Cats are working.

The engine seems to be running fine. Could it be Evap components? Purge or vacuum valve?
I replaced the gas cap and then the next time I filled up, the tank sucked in air for about 10 seconds.

I am a bit lost on what to check next.

It's either cat or the O2 sensors.

Quote
jfaltys
I know this is an old thread. I am getting p0430. My O2 Sensors pass the the IM test, but getting the po430 code. I have replaced the plug tubes, and AOS because I was getting oil leaks and some smoke, which have now cleared up, but the code still shows.

In graphing the o2 sensors voltages, I get wide variations on the pre cat sensors and fairly flat on the post o2 cat sensors.
So I believe that is telling me that my O2 sensors are working and my Cats are working.

The engine seems to be running fine. Could it be Evap components? Purge or vacuum valve?
I replaced the gas cap and then the next time I filled up, the tank sucked in air for about 10 seconds.

I am a bit lost on what to check next.

From my experience with my 2002 Boxster I am very familiar with the P0430 error code. Converter operating below efficiency. From the factory manual if the P0430 (or P0420) error code is accompanied by any O2 sensor error codes replace the sensors indicated, clear the codes, road test the car. If the P430 (P0420) error code comes back replace the indicated converter.

The wide variations in voltage level readings from the #1 O2 sensors is normal. The engine controller varies the amount of fuel injected on either side of what would be ideal. At idle this happens at around a 1Hz frequency. Monitoring the voltage levels using an OBD2 data viewer the voltage level will range from 0.1V to over 0.7V. The low voltage signals an excess of oxygen in the exhaust gas. The engine controller didn't inject quite enough fuel and not as much oxygen was consumed. The higher voltage signals an absence of oxygen. The engine controller injected a bit extra fuel and more of the oxygen was consumed.

The "excess" oxygen is caught by the converter and stored then it is given up in the converting of exhaust gases.

The #2 O2 sensor readings want to be around the 0.7V range. This is an indication the converter is storing/consuming the excess oxygen the engine controller causes to be in the exhaust gases. Actually the voltage level will vary a bit as the converter reflects the varying level of oxygen it is receiving. But it doesn't want to be much below 0.7V. If the voltage level drops below 0.45V this is a sign oxygen is not being captured by the converter and, well, the converter is performing below efficiency.

With a P0430 (P0420) error code is it unlikely the fuel ventilation system is acting up. If it was to the point it could possibly affect the converter operation there would be a CEL and error codes pointing the fuel ventilation system or at least a fuel mixture problem.

The same applies to other possible -- but based on the factory manual unlikely -- causes of the P0430 (P0420) error code.

'course, you have to be sure there are no other issues with fueling. No intake air leaks, fuel pressure ok. I trust there are no *pending* error codes of any kind?

If there are no other issues that could possibly account for the converter's poor performance the odds are high the indicated converter is just bad and to address the P0430 error code the converter will need to be replaced.

In most areas you can source a good used converter. In CA this is I understand against the "law". There are supposed to be CARB certified replacement converters available at I guess less cost than factory replacement converters but I have no experience with thise CARB certified replacement converters. The factory converters which a few years ago when I got a quote on new ones ran over $1000/each.

Used ones were $450 (or was it $495?) each. I can't recall now. Even at $450/495/each still rather expensive but still less than half the cost of new ones. But you have to be sure the used ones are in good condition.

When I bought a couple of used exhaust manifolds with of course the converter I first shook each one vigorously to make sure the brick was not loose nor was the brick coming apart, shedding any material. Then after I was satisfied the two exhaust manifolds/converters were good I handled them with kid gloves. No throwing them in the trunk and letting them bang against each other. A Porsche tech replaced them and they both proved to be in very good condition and no more P0430 error code.

This is very helpful info. I have to add some additional info.
I have 3 codes, no pending. P0430, P0410, P1411

I tested the pump/air injection system and found that my hoses are old and the Air pump control/shut off valve is bad. So I have the intake manifold off waiting for those parts.

Once I re-assemble, I hope/assume it will get rid of p0410 and p1411. Then I will rerun the odb2 o2 sensor monitors and determine if the voltages fall in line with your post.
Thank you
John

Quote
jfaltys
This is very helpful info. I have to add some additional info.
I have 3 codes, no pending. P0430, P0410, P1411

I tested the pump/air injection system and found that my hoses are old and the Air pump control/shut off valve is bad. So I have the intake manifold off waiting for those parts.

Once I re-assemble, I hope/assume it will get rid of p0410 and p1411. Then I will rerun the odb2 o2 sensor monitors and determine if the voltages fall in line with your post.
Thank you
John

Of course address those additional codes. While factory manual didn't mention any additional codes with the P0430 (P0420) error code, other than any O2 sensor codes, you certainly want no other active codes, no pending codes, and ideally no "permanent" codes. ("Permanent" codes can only be cleared by the engine controller after so many engine warm up cycles with the error condition absent.) And you want to see all readiness monitors set complete.

'course, if you find you can't seem to get the converter readiness monitor set to complete, possibly even the O2 sensor readiness monitor set to complete, with or without a CEL and error code, then likely the converter is still acting up. It can just be bad. But given how much a replacement costs you want to be darn sure of your diagnosis.

This is one reason why one can put some *trust* into a P0430/P0420 error code. Porsche as is true with all car makers is on the hook for a bad converter while the federal emissions warranty is in effect. I think this warranty runs 8 years, 80K miles. If the P0430/P0420 error codes were easy to generate, due to spurious conditions, Porsche could be facing having to replace these under warranty. Still, eliminate the source of the other error codes, just to remove any thing that could even remotely contribute to a P0430/P0420 error code.

I have cleared all codes but p0430.
I also swapped out the 4 o2 sensors as fairly inexpensive compared to Cats. But the code still remains.
I have 2 questions
See the image below O2S2 B1 seems like it is the post cat O2 sensor and O2S2 B2 looks like the pre cat. And that cat looks like it is working.
1. Am I right that the B1 should be post sensor? If so, is it possible that the wiring is switched at the computer?
2. O2S1 looks like that cat is bad. Agree?




Thank you

Try the image again.
[drive.google.com]

After reviewing the data more, I believe my post above is incorrect.
In the picture B1 looks fine. S1 bank 1 and S2 bank 1 look perfect.

S1 bank 2 looks ok, but S2 bank 2 looks like the catalytic converter is not working correctly.

Thank you for any feedback.

Quote
jfaltys
After reviewing the data more, I believe my post above is incorrect.
In the picture B1 looks fine. S1 bank 1 and S2 bank 1 look perfect.

S1 bank 2 looks ok, but S2 bank 2 looks like the catalytic converter is not working correctly.

Thank you for any feedback.

Just a few second's worth of voltage readings is not a lot to go on but with my Boxster the times I viewed the O2 sensor voltage output when the P0430 code had just shown up the voltage readings dipped quite a bit. This is a signal oxygen is flowing through the converter rather than being captured by it and used to process exhaust gases.

Almost certainly the P0430 is only triggered after much more data sampling and perhaps accompanied by some time measurement to see how quickly the converter can react to changes in the oxygen content of the incoming exhaust gases. Thus the degree to which the voltage level varies but also the time it takes is used to flag a converter good or bad.

Agreed.
However, if those voltages are sustained over time, would that imply that Cat on Bank2 is bad?
I drove for about 45 minutes, and Bank 1 did not look good until about 15 minutes (I assume when it was hot enough) and then the o2 sensors were consistent to what is seen in the picture.
Similarly, bank 2 never really varied from the pattern in the picture for the entire drive.

Thanks again.

Quote
jfaltys
Agreed.
However, if those voltages are sustained over time, would that imply that Cat on Bank2 is bad?
I drove for about 45 minutes, and Bank 1 did not look good until about 15 minutes (I assume when it was hot enough) and then the o2 sensors were consistent to what is seen in the picture.
Similarly, bank 2 never really varied from the pattern in the picture for the entire drive.

Thanks again.

15 minutes for a converter to get hot enough does not jive with my understanding and experience of how the converters work. With my Boxster after just a bit of idling -- how long a "bit" was dependent upon ambient temperature but around a minute was the longest this took -- then when the secondary air injection pump shut down and the elevated cold idle speed dropped to near normal hot idle speed the engine controller had switched from open loop mode to closed loop mode -- which I confirmed more than once by monitoring this status via an OBD2 code reader/data viewer -- because the sensors and the converters (the pre-converters the ones located in the exhaust manifold and the only ones monitored) were up to operating temperature. My 996 Turbo engine behaved the same way.

Not sure why you seek to duplicate what the engine controller has done. It has already decided the converter is not operating at a sufficient level of efficiency. If the car was under the federal emissions warranty Porsche would be giving you a new converter. 'course, I should talk. I went some weeks trying to catch the bad O2 sensor in the act, so to speak. And likewise with the converter I had the error code, and the knocking when cold and buzzing when hot, yet I wanted to see what the sensor reading was around the time the CEL came on. Curiosity I guess.

Charlie and Omar are widely considered to be some of the most knowledgeable P-Car guys in the area - lot's of high end track hardware goes there for service.

They have never steered me wrong and they REALLY know what they are talking about.

The oil in the cats theory sounds reasonable, but I would check the oil filler tube or AOS vent line first.

1998 986 Turbo-Look Cab
172,000 Miles
Dilithium Crystal Supercharger

Jeff,

I just went through this. I had a P0430 on an 01'S I recently bought.
The P0430 meant low efficiency on the primary cat, driver side.

While under the car, I noticed the O2 sensor (pre-cat) had been changed recently.
So I guess that the bad O2 sensor made the engine run rich, which destroyed the cat.
On my car, the cat was really bad. When I removed it, it was almost empty.
The cell mesh inside was separated from the housing, and was ~ half its original size.
What was left was floating around. Efficiency must have been really low !
I could also hear a rattle coming from the cat.

Another way to diagnose if your cat is bad would be to use an infrared thermometer.
Run the car for 1 minute, and check the temperature of the cats. My bad cat was a lot colder than the other bank. Those things run hot, when in good shape.

Finally, I got replacement cats for free ! There are racers out there with performance headers and they have the original cats laying around.
A used one may not last long, but it's better than $3K ! Just ask on the forums... There are nice people out there !
If you change the cats, make sure you check your pre-cat O2 sensor, there's a reason while it failed, and you don't want to destroy the new ones too quickly.

You can also diagnose O2 sensors by swapping them. If the code changes (other bank) and follows the O2 sensors, you know it's a bad sensor.

Good luck,

-Guillaume