aeshultz

I've got a driver's side cat going bad, CEL light just last night, pulled the codes with a Durametric reader;
"P0430 / Fault Code 45 -Cat conversion bank 2 - exceeds limit value"
Bentley manual says "TWC conversion cylinders 4-6, short to ground, below lower limit, lean mixture threshold."
What is this telling me in plain english?
and is the car drivable - the "lean mixture threshold" worries me.
TIA

Macster

Converter Bank 2 operating below effiiciency.

Ok to drive as long as the light is not flashing and the engine or car is not manifesting any symptoms that suggest trouble.

My 02 has been generating this error code every once in awhile -- more frequently in the colder months, nearly never in summer months -- for several years now.

Converter wearing out. The converter is tested by the Ecu using the #2 O2 sensor to verify that the converter can store sufficient oxygen in 4 speed/load ranges. If it can't in 3 of the 4 this error is logged.

Based on my experience you can clear the error code. If near an oil/filter service run a bottle or two of Techron through the gas tank -- follow directions on the bottle -- then after the tank with the Techron low enough to add gas change the oil/filter.

Use a guality top tier gas, premium, and buy from a busy station.

Be sure air filter fresh.

When my car was due -- 2 years ago -- for a smog check I had the spark plugs changed. They were close to being due on miles. In fact, IIRC they were overdue.

Car passed its smog check/test easily.

This last time I didn't bother with the plugs. They have around 40K miles on them and well I just wanted to see if I could get by without changing them.

Car passed its smog check this last May though not with as much margin this time as last.

CEL with P0430 came on day after smog test. Have an Actron OBDII code reader/data viewer in the car so I just connect this, read the code, confirm it is a P0430 code, then clear the code -- can't stand the CEL on -- and drive car normally.

One of these days, when I have to, I'll replace the failing converter and possibly the other one as well since I like to think it is best to have both converters the same age to ensure close to the same exhaust gas processing on both banks to keep the Ecu controlller from having to supply quite dissimilar adaptations to the two different cylinder banks.

Sincerely,

Macster.

aeshultz

Thank, Macster - that's good info.
I know that the drivers side (bank 2) secondary cat is going bad - rattling and making noise. I ws about to change the oil JFTHofit, but I think I'll try the Techron and then change. I'm pretty sure I'll change the cat or delete it soon.

aeshultz

And does anyone know - the "* years and 80,000 mile" warrantee on cats - is that 8 years "or" - whichever comes first, or either?

Macster

As best I can tell neither of my car's warm up converters or the larger converters make any noise. The car has nearly 234K miles so in my car's case I can believe the converter is just wearing out. I've worn out a couple of AOSs, one MAF, maybe 4 O2 sensors, one water pump, one fuel pump, so it would not surprise me the converter is just worn out. Actually I'm more surprised, but still pleased, they have lasted as long as they have.

If you hear noise coming from any of your car's converters Techron might still called for on general principles of periodically (every 1 to 2 years) treating the fuel system and engine to whatever cleaning Techron provides, but it will unlikely improve the converter's performance.

The noise strongly suggests there has been a mechanical failure and this accounts for the under-performing converter. Because of this mechamnical failured, exhaust gases might *not* be flowing equally to all active converter surfaces and the converter appears to be worn out when it is just broken.

My info is, well, my memory of it is, the warranty on emissions items, and this includes converters (but not much else) is 8 years, or 80K miles, whichever comes first.

Sincerely,

Macster.

aeshultz

Yes, I believe that it's a mechanical failure.
So 8 years _OR_ 80,000 miles, whichever comes first. Bummer. I'll check w/ a dealer JIC.
Thanks for the help.

LammMorada

My 2001 S showed a P0430 fault code about 18 months ago, at around 89K miles. Taking the code at its word, I duly ordered a new pre-cat from Sunset and installed it. I do as much mechanical work as I can myself, and the pre-cat was an easy installation.

The CEL stayed unlit for about 3000 miles, whereupon it flashed back on. Big surprise. Same code: P0430. I figured it might be the driver-side pre-cat this time, but that didn't really make sense since P0430 specifically indicates the passenger's side.

So I took the car in to our local Porsche shop, and they found a P1126 fault code lurking in the system, in addition to the P0430. My code reader hadn't found the P1126 code. The P1126 means "oxygen sensing adaptation, lower load range, bank 1." The shop mechanic told me that it sometimes takes more specialized equipment than a simple code reader to find certain faults...plus you don't always take fault codes literally - that over time he's learned to interpret what they mean.

In my case, the two codes together had nothing to do with either catalytic converter or pre-cat. I could have saved myself the time and money of replacing my passenger-side pre-cat. Instead, the two codes together indicated replacing the fuel-pressure regulator and the mass airflow meter (MAF), which the shop did, and my CEL hasn't lit up since (I'm now at 95K miles).

I pass this information along for what it's worth, the point being that you shouldn't necessarily believe, literally, what your code reader tells you.

Macster

You raise a good point. In my car's case my code reader can read -- it can't "interpret" though but I have access to some of the Porsche proprietary P1xxx code definitions -- the P1xxx codes so I know the P0430 is the only code. The O2 sensors have been replaced and the fuel pump which failed recently was replaced. The P0430 code has been around now for quite some time and I am convinced it is the converter.

But I'm not going to to replace it until I have to.

In the OP's situation from his decription of the symptoms, the error code, the noise, almost certainly the converter's the problem.

But as you wisely stated, it is a good thing to be very sure.

Added: One of my references lists the TWC (three way converter) as the only possible cause. However in the diagnostics/trouble shooting section it provides several steps that involve testing the functionality of the vapor recovery system.

I think this is a serious printing error/mixup so I didn't bother to even list the diagnostics steps.

Another source gives more realistic sources of the error. They are (in the order in the reference): oxygen sensors ahead of and after TWC swapped; valve lift fault (from my 996 Turbo reference which may not apply in all other cases since for instance my 02 Boxster engine does not have the VarioCam Plus feature); aged oxygen sensor after TWC; and TWC faulty. Since in most cases the TWC is a warranty item you know it is going to be listed last.

Now my info is the TWC might be off the hook if along with the P0430/P0420 error code an oxygen aging error code is logged. At least one could replace the aging oxygen sensor and see if the error returns. In fact, one can if he is careful simply swap the two #2 sensors from side to side. They are interchangable and see if the error follows the sensor or stays with the converter.

The reference lists eliminate sensors, peform system test for proper small valve lift, or replace the TWC.

Sincerely,

Macster.

aeshultz

Thanks for the info, guys. I've got a pair of converters on the way, will let you know it that solves it.
BTW- "Bad cat" was the original diagnosis from a dealer - not that they are infalible, but at least it's another data point.

originalmotorhead

FWIW, Everytime I pop open the top engine access(whether to clean the engine, check air filter, whatever), I always remove the MAF sensor and hose it out with brake cleaner and then reinstall. I've got a cone filter / airbox setup and I don't over oil but I've heard before that it's good to clean the MAF's periodically. I used to get a code about once a year, by cleaning, it would go away. And I drive my car a lot so it's not like it takes me long to put 300 ish miles on(I have 250 miles a week in work commute).

Had I known sooner, I have my old cats in the garage, all four of me :P (no not the 4 leggid kind either)

Tom

Macster

That doesn't sound good to me. Except the 1st time the AOS acted up -- around 80K miles -- and then once again -- more recently but I can't remember the miles -- when I suspected a bad MAF (turned out to be a leaking oil filler tube cap) and even more recently when the replacement MAF (replaced before I discovered the leaking oil tube filler cap) -- again I can't remember the miles -- I don't make MAF cleaning a part of any service schedule for my Boxster (or any other car).

My Boxster, now with 233.8 miles, has run on average nearly 80K miles between MAF cleanings and these were done because of specific symptoms which suggested the MAF might be at fault and in the case of the 1st time due to my inexperience and others' advice I cleaned the MAF in the hopes it would eliminate the symptoms. It wasn't dirty then, it has not been dirty the other times I've cleaned it.

Furthermore, I've never cleaned the MAF of my 03 Turbo (which has accumulated 30K miles in 13 months for a bit over 40K miles total) , nor my 06 GTO that in a couple of years accumulated nearly 40K miles, nor the 02 VW Golf Tdi that I sold in early 2006 with over 120K miles and so on.

If you are having to clean the MAF cause it is dirty the air filter system you have is not doing its job. It is not filtering the dust out of the air. While you can clean the MAF and restore its function, you can't add back the engine metal the dust particles remove once they get past the filter and into the engine and its oil.

IOWs, the having to clean the MAF yearly is the symptom not the cure. The disease is an inadequate air filtering system

Sincerely,

Macster.

originalmotorhead

I just made it a part of my routine, whether needed or not. Friend of mine had a supercharged toyota 4x4 and the dealer told him to clean the maf annualy to avoid a CEL. Sounded like a good and simple practice to me. Now granted I 'only' clean it when I do pop the top cover so that is hit or miss but it's a minute 'extra' and no skin off my back.

I'm at 90+k and still going strong. Granted I live at the end of a chip and seal road so I try to clean the air filter once a year but even that is dependent on my mood that weekend

maybe excess but I am ok with that. Like they say, YMMV

Tom