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Old 12-19-2013, 10:49 AM   #1
markgbe
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P0430 Catalyst System Efficiency Below Threshold (Bank 2) Has anyone solved this?

So i'm getting this code, p0430. I did a ton of searching but i cant find a thread where the person came back and said what fixed it.

I'm really hoping this is not cats. I was going to go the cheap route first and replace the post cat O2s.

Has anyone had experience with this? Thoughts?

Last edited by markgbe; 12-19-2013 at 10:58 AM.
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Old 12-19-2013, 10:59 AM   #2
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Replacing the catalytic converter will solve the problem, but for how long and is the code indicating the converter is actually bad or is this a symptom of other fuel management issues that have been going undetected.

Start with the basics of engine temperature. Needs to be correct, otherwise the sensors and converters can carbon up.

You need an OBDII scan tool to start watching fuel trims and finger printing the O2 sensors from cold start.

https://forum.e46fanatics.com/showthread.php?t=967204

Questionable O2 sensors, O2 bung weld cracks, exhaust leaks and many other things could contribute.

Start with the simple things, converter would be the last thing I would consider replacing due to cost and difficulty.
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Old 12-19-2013, 11:27 AM   #3
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I cleaned mine in soap and water and it works as long as its just ash depositscand not broken inside.
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Old 12-19-2013, 12:26 PM   #4
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Originally Posted by Loaded325i View Post
I cleaned mine in soap and water and it works as long as its just ash depositscand not broken inside.
The Scotty YouTube clean up!!
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Old 12-19-2013, 01:00 PM   #5
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Quote:
Originally Posted by markgbe View Post
So i'm getting this code, p0430. I did a ton of searching but i cant find a thread where the person came back and said what fixed it.

I'm really hoping this is not cats. I was going to go the cheap route first and replace the post cat O2s.

Has anyone had experience with this? Thoughts?
The issue is one of two things, a failing/failed sensor or a failing/failed CAT.

You can test by taking the after CAT sensor out of the car and putting the other one in its place, then putting the first one in the hole thatthe second one came out of. DO NOT simply move the sensor but leave it plugged into the same connector -- completely remove the sensor from the car by disconnecting it, then move it to the other side and plug it in again.

If the CAT is the trouble, the code will remain the same because the same CAT will be read by a different sensor.

If the sensor is the trouble then the code will become P0420 instead of P0430, or vice versa, because the defective sensor is now on the other side.
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Old 12-19-2013, 01:01 PM   #6
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CAVEAT
A CAT Below Threshold problem can be caused by an exhaust leak. In this case, the code would still remain the same when the sensors are swapped.
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Old 12-19-2013, 01:36 PM   #7
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Quote:
Originally Posted by jdstrickland View Post
The issue is one of two things, a failing/failed sensor or a failing/failed CAT.
Not correct, there are PLENTY of other things that can trigger Cat efficiency codes. Everything to something simple like a bad thermostat, exhaust leaks, bad or counterfeit MAF's to swapped sensor wiring and so forth.

You can have a bad cat or sensor, but there is a lot more to this than you would think.

Swapping sensors as you mentioned above will not be so straight forward and I believe you have the outcome listed backwards, assuming there are not other unexpected things that pop up out of swapping the sensors with the wiring still attached.

Not sure this is a sure fire way to troubleshoot the issue.
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Last edited by jfoj; 12-19-2013 at 01:39 PM.
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Old 12-19-2013, 02:13 PM   #8
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A bad MAF or t-stat would not cause a single-side CAT problem. They could cause an error of both CATs, but should not produce an error of one CAT but not the other. When one or the other CAT is reported with an error, it is most likely a bad CAT or a bad sensor, and because the sensor is more delicate than the CAT, then I would look to isolate the the sensor.

I said that an exhaust leak could give a code for a bad CAT.

If you swap the sensor for Bank1 and Bank2, then if the problem remains the same then the CAT or an upstream leak has to be the problem, and it the problem moves to the other side -- follows the sensor -- then the sensor itself has to be the problem.

I concede the point that other upstream issues can be the source, but swapping the sensors should tell you that the sensor is failing or not. One needs to see if the problem changes or not when the sensors are moved. If the same side reports an error, then you start to isolate the exhaust system for that side, and then the intake track. If the problem follows the sensor then you give serious consideration to the idea that the sensor is failing.

I recently got a P0430 code on my truck. I also have a rattle from the CAT on Bank2. I really don't want to buy a CAT, so I diagnosed the sensor by moving it to the other side and hoping that the problem would become P0420. No joy. I still get a P0430, so I have trouble with the Bank2 CAT, or something upstream that is unique to Bank2.
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Old 12-19-2013, 02:29 PM   #9
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Upstream errors can in fact cause a single cat efficiency code, not everything is as straight forward as everyone thinks. Just like a common vacuum leak can trigger lean codes for just 1 bank, depends on a lot of other factors and if there is a smaller secondary leak.

Everything has a threshold before a DTC is triggered, some things degrade or change at a different rate than others. You have no idea is the other cat efficiency code on the edge or not even close to triggering.

All the cat efficiency codes need a lot of diagnosing and do not jump to conclusions with the data. If you want to jump to conclusions, just replace the cat and hope there is nothing causing it to degrade!

Its all about the $$$$. Also the cat efficiency codes can usually be managed if you need to get a SMOG inspection anyway, so I do not get overly excited about them.
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Old 12-20-2013, 10:28 AM   #10
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yay, the code went away by itself. i'll be checking for intake / exhaust leaks anyway and replacing all o2 sensors since my car has 116000 miles.
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Old 12-30-2013, 09:50 AM   #11
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the code ended up coming back. I checked engine temp and it's right on. Checked for any intake/exhaust leaks and nothing. The car is running great.

I will be swapping the rear o2 sensors sometime this week to see if the p0430 code turns into a p0420 code.

Any suggestions in the mean time?
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Old 12-30-2013, 12:33 PM   #12
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Quote:
Originally Posted by markgbe View Post
the code ended up coming back. I checked engine temp and it's right on. Checked for any intake/exhaust leaks and nothing. The car is running great.

I will be swapping the rear o2 sensors sometime this week to see if the p0430 code turns into a p0420 code.

Any suggestions in the mean time?
It is a lot easier to just plug an OBD scanner into the car (bluetooth ones are $15 on ebay) and read the pre cat readings and the post cat readings. If the cat is bad, usually the pre cat and post cat readings will be almost identical. Easier than swapping post cat sensors.
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Old 12-30-2013, 12:39 PM   #13
markgbe
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Originally Posted by smolck View Post
It is a lot easier to just plug an OBD scanner into the car (bluetooth ones are $15 on ebay) and read the pre cat readings and the post cat readings. If the cat is bad, usually the pre cat and post cat readings will be almost identical. Easier than swapping post cat sensors.
i have the bluetooth connector and torque app and there are a ton of different readings i can check. Which would be the pre cat and post cat readings that i'm interested in?

i think guessing it's one of these..

catalyst temp bank 1/bank 2
o2 sensor voltages
o2 sensor equivalence ratio
fuel trims bank 1/bank 2

Last edited by markgbe; 12-30-2013 at 12:39 PM.
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Old 01-24-2014, 06:44 AM   #14
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Figured I'd update with my results. I ended up replacing my valve cover gasket because it was leaking bit. I figured it was probably sucking in extra air. Well its been weeks and no ses light.
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