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Old 04-19-2011, 03:38 PM   #1
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P0430 Code - 2001 Boxster

I've been to a few places that read the check engine light code on OBD IIs. It seems they all read the same code P0430.

The reader stated the code was for "Bank 2" catalytic converter.

In order to make sure it was not the O2 sensors, I switched the passenger side and drivers side O2 sensors and stil got the same code. I know this does not eliminate other issues causing problems but I now know it was not the O2 sensors.

One question I cannot find the answer to is this -

Does "Bank 2" correspond to the drivers side or passenger side?

Thanks! This one has got me stumped as I've heard different things from different folks around my parts.
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Old 04-19-2011, 04:44 PM   #2
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Bank 1 is the passenger side of a US car. Bank 2 is the driver's side.

Bank 1 consists of cylinders 1,2,3 from front to rear.
Bank 2 consists of cylinders 4,5,6 from front to rear.
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Old 04-19-2011, 06:05 PM   #3
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Quote:
Originally Posted by AtlantaBoxster
I've been to a few places that read the check engine light code on OBD IIs. It seems they all read the same code P0430.

The reader stated the code was for "Bank 2" catalytic converter.

In order to make sure it was not the O2 sensors, I switched the passenger side and drivers side O2 sensors and stil got the same code. I know this does not eliminate other issues causing problems but I now know it was not the O2 sensors.

One question I cannot find the answer to is this -

Does "Bank 2" correspond to the drivers side or passenger side?

Thanks! This one has got me stumped as I've heard different things from different folks around my parts.

Is P0430 the only alarm you have???

Jager
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Old 04-20-2011, 03:48 AM   #4
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thstone - Thank you very much. It is good knowing this forum is available to get this kind of information.

Jager - Yes, that is the only code that shows up on the different readers.
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Old 04-20-2011, 06:00 AM   #5
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diag info

Diagnosis conditions
• TWC temperature 420 - 600 °C
• 85 seconds within rpm/load range (cumulative)
• EVAP canister burden < 8
• Speed 1280 - 2440 rpm
• 20 - 40 % engine load (relative air charge)
• Oxygen sensing ahead of TWC is active
• Oxygen sensing after TWC ready for operation
• Engine starting temperature > - 20 °C
• No faults in memory
Possible fault cause
♦ Oxygen sensor ahead of and after TWC exchanged
♦ Valve lift fault
♦ Aged oxygen sensor after TWC
♦ TWC faulty


HTH

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Old 04-20-2011, 07:24 AM   #6
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A P0430 code means that the oxygen sensor downstream of the catalytic converter is detecting that the cat is not working properly. This results in higher emissions. Odds are that the car drives fine.

Likely causes are:
Exhaust leak
Intake leak
O2 sensor not working properly (could be either O2 sensor on Bank 2)
MAF (not likely but cheap to clean)
Cat not working properly

Most people start by looking for exhaust and intake leaks and if all seems well there then they replace the O2 sensors. Otherwise work your way down the list, and please note that its rare that the actual cat is bad. Its usually something else.
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Old 04-20-2011, 08:37 AM   #7
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What I've done so far.

1) Moved O2 sensors from one side to the other - Still get P0430 code.
2) Just cleaned MAF sensor yesterday - waiting to see if code will pop up again. Never know how long it takes. Was replaced 2 years ago. Looked prestine.
3) Recently changed air/oil seperator.

thstone

I am not sure how I could check for exhaust or intake leak - Will google that. I 'm thinking I need a smoke generator of some sort though.

paulv - I must say you've thrown me for a loop in many of your diag suggestions.

You obviously have much more experience than I do. Are the items you detail relatively easy to do once I understand what they mean?
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Old 04-20-2011, 11:00 AM   #8
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Quote:
Originally Posted by AtlantaBoxster
1) Moved O2 sensors from one side to the other - Still get P0430 code.
2) Just cleaned MAF sensor yesterday - waiting to see if code will pop up again. Never know how long it takes. Was replaced 2 years ago. Looked prestine.
3) Recently changed air/oil seperator.

thstone

I am not sure how I could check for exhaust or intake leak - Will google that. I 'm thinking I need a smoke generator of some sort though.

paulv - I must say you've thrown me for a loop in many of your diag suggestions.

You obviously have much more experience than I do. Are the items you detail relatively easy to do once I understand what they mean?
The P0430 most likely a 2 drive cycle code which means that you would have to drive twice (shutting it down, cooling off, start up again and drive a mix of idle and cruising) to see if the CEL will come on again with the same code.

Are the two aft O2 sensors still swapped?

And yes, the best way to find a leak is with a smoke machine. Any place (the cat convertor, near the O2 sensor, etc.) that will allow for air to come in will throw the reading of the aft O2 sensor off. Also check the wiring harness/connector to the O2 sensor.

From reading the code, did you get any freeze frame data? If you had it read at a parts shop, go back and see if the scanner they use provides FF data -- if so, get that info and post here.

Regards,
paul..
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Old 04-20-2011, 11:48 AM   #9
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paulv

Yes, the O2 sensors are still swapped. I did not move them back. Since I switched all the O2 sensors, I did remove and put back the harness. If the harness was not seated properly, would I get a P0430 code or something else?

Just ordered this little jobby. Will see how well it works. Only $38 bucks, worth the risk. Seemed fairly decent reviews.

I'll let you know the results after I test it.

http://www.amazon.com/Crescent-OBD2-Multi-Protocol-Diagnostic-Scanner/dp/B001MT0XPK
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Old 04-20-2011, 07:57 PM   #10
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Per Paulv's earlier post that listed possible causes, don't ignore the O2 sensor in front of the cat.

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Old 04-21-2011, 03:47 AM   #11
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Quote:
Originally Posted by AtlantaBoxster
paulv

Yes, the O2 sensors are still swapped. I did not move them back. Since I switched all the O2 sensors, I did remove and put back the harness. If the harness was not seated properly, would I get a P0430 code or something else?

Just ordered this little jobby. Will see how well it works. Only $38 bucks, worth the risk. Seemed fairly decent reviews.

I'll let you know the results after I test it.

http://www.amazon.com/Crescent-OBD2-Multi-Protocol-Diagnostic-Scanner/dp/B001MT0XPK
O2 sensors send signals back to the DME module. If the DME doesn't receive a [proper] signal, then a code will be generated. The only reason that there's a rear O2 sensor is to measure the cat conv's efficiency (under OBD2, not part of OBD1) -- the efficiency is the measure of how well the cat conv stores oxygen. Typically, the DME will look at the signals from both the fore and aft O2 sensors in order to determine if the aft O2 sensor is telling the "truth" -- thus, this is what Jager was talking about and is also in the diagnosis conditions I posted earlier.

As O2 sensors age, they get "lazy" -- which means that they don't switch as fast as they used to -- this would also generate the P0430 code.

If you have access to a graphing multimeter (or preferably an oscilloscope) you can watch the voltage signal coming out of the O2 sensor (and compare both banks) to isolate whether the O2 sensor is on the borderline of failing or it it's something else.

Also, I don't know if your year model has an O2 sensor as the fore sensor or if it has an air/fuel ratio sensor (aka: wideband O2 sensor) -- these don't have a switching voltage but they generate a current that changes polarity whether the mixture is rich or lean and stay at zero when the mixture is at the proper 14.7:1 (air to fuel). Some scan tools will convert this current to a voltage so it can be viewed easier, but not all scan tools do this.

Also, send me a PM with your email so I can send you the diags document (where I got the info to post earlier) and a DIY tutorial from a company that makes scan tools -- it's a nice intro to all this stuff. Can't post either here -- the diags doc is copyrighted and the DIY tutorial is too large.

What year is your car? I'll check to see if there's a TSB out on this issue.

Regards,
paul...

Last edited by paulv; 04-21-2011 at 03:53 AM.
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Old 04-21-2011, 07:04 AM   #12
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Thank you Jager.

Paulv, I sent you a pm.
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Old 04-25-2011, 08:41 AM   #13
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Problem Solved - Code Cleared - Emmisions Passed

I want to thank you all for helping me out on this one. The last thing I did was a simple and less than $7 fix vs. the prescribed dealer price of $1800 for a new cat (even though I found a 400 cell after market for $450 delivered).

After switching the O2 sensors from one side to the other and still getting the same pesky P0430 code, my next step was to clean the MAF sensor.

Very simple process. I had forgoteen to buy the right Torx tool and therefore used a vise grip to remove the two screws. Only cost was some time and the bottle of electronic cleaner I picked up at the local auto parts store.

Have run the car over 300 miles without check engine light coming back on. Went to get emmisions done today and passed!

Perfect and thanks again.
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Old 12-04-2012, 04:01 PM   #14
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I had the same thing. Engine Light diagnosis code # P0430.
I stopped at Mobil for gas twice, and had a three hour drive, and ran it like it was stolen. Light came off. I am going to dump a bottle of techron too, why not!?

"Porsches are meant to be driven not polished"

The shop only sees mine from a back of a tow truck.....

No affiliation, just making my point
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Old 12-04-2012, 05:26 PM   #15
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I too have 2001 box and also P0430.
the CEL with this code come up only when the car is driven on a flat road with the cruise control on.
if driven hard, the code does not appear.
I've search this site and concluded that the O2 sensors are getting old and lazy. will replace all four some time in the near future.
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Old 05-25-2015, 01:50 PM   #16
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Hi everyone:

I've occasionally seen a P0430 code on my 01S over the last 12 months. I've been trying to make sure its the cats causing the code before I spend the big bucks to replace them.

My understanding is that the after-cat O2 sensor voltages will look flat if the cats are working properly. If the cats are weak or bad, then the after-cat O2 sensor voltages will fluctuate like the pre-cat sensors.

Is this true? Is it is, are there any other conditions other than a weak or failed cat which would cause the rear O2 sensor voltages to fluctuate. Or does fluctuating rear O2 sensor voltages pretty much confirm the problem.

Thanks
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Old 05-25-2015, 02:18 PM   #17
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The CAT "expects" (by design) an exhaust gas mixture that it can successfully clean up. If it doesn't get it the output from the cat won't be clean, obviously. In many instances the reason the cat doesn't get what it wants is a malfunctioning MAF. It all starts at the MAF and a "bad CAT" code may be the result but not the cause.

IMHO the weak link in the system is most often the MAF. CATs are required by law to last for 8 years/80k miles or else it's a free warranty replacement. 986 original cats are all past warranty of course, but the point is they are pretty tough designs.

I'm not positive, but I expect the only thing that will generate a bad MAF code is an electrical fault in the MAF itself. If it's just not creating a proper mixture that can be burned efficiently, expect codes most often for downstream components. But look at the MAF first. And, I'd expect the success rate for just "cleaning" the MAF to be small.

Discussion?
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Old 05-25-2015, 06:51 PM   #18
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Here is my P0430 story:

http://986forum.com/forums/general-discussions/47002-calling-986-forum-master-mechanics-2.html
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Old 05-25-2015, 08:02 PM   #19
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If you need to replace the cats, why not go with this set?

Removed the link. Company did not go through with the sale. I'll have to say steer clear of Vivid Racing when buying parts.

My cats are bad, due to a slow leaking AOS mucking them up. I ordered a set of the above headers last Friday. Secondary cat delete pipes, resonators and Borla muffler setting here waiting for them.

My O2 sensors were bad too, have nice new O2 sensors waiting on the headers too.
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