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P0430 Catalytic Converter

41K views 17 replies 7 participants last post by  jarair75 
#1 ·
Hey guys!

I have a a new code popped on my truck. It is P0430 (Catalyst System Efficiency Below Threshold Bank 2).
I don't have any bad smell coming from the tailpipes, haven't noticed the loss in power. Although I think my 14mpg is a bit high....
I've read and watched tons on stuff online and people tell not to just replace the O2 sensor so I'm thinking putting an O2 spacer in.
What is the thread size on the O2 sensor? I have one that throws code on the passenger side that goes into the cat (the rear one).
Maybe someone experienced this problem? Any help would be nice :smileup:

And yeah, 183K miles.... I'm gonna replace the cat but not at this moment...
 
#2 · (Edited)
P0430 - Catalyst Effeciency BANK 2 You will have one O2 sensor before (Upstream) the catalytic converter and one O2 sensor after (Downstream) the catalytic converter. Any of the 4 O2 sensors can cause this code to set.

This code can be set due to a number of things. Do you have any exhaust leaks (These trucks are very common for exhaust manifold leaks due to broken studs), misfires or any other mechanical issues with the engine that you're aware of? When is the last time you changed the spark plugs?

It can be caused by O2 sensor wiring, connections, Open circuits, shorting to ground, shorting to voltage, etc.

It can also be caused by aged or failed O2 sensors. The upstream O2 sensors tend to carbon up over time and the downstream O2 sensor will stay reletively cleaner after the Cat. These trucks have 4 O2 sensors (2 on each cylinder bank), 2 upstream and 2 downstream. It is recommended that they all be replaced at the same time if you determine that an O2 sensor is at fault. By replacing one 02 sensor out of 3, the new O2 sensor may read slightly different voltage due to being clean and the others carboned and throw the code also (According to Dodge Specs).

Worst case scenario if everything else checks out is a failed catalytic converter. You should be able to inspect it with a flash light after removing the exhaust down pipe from the exhaust manifold. It should have nice white honeycomb and no dents, cracks or holes/melting.

If your engine has been running good mechanically, ie not dumping fuel/misfiring, damaged by impact, your catalytic converter should be fine.

I've given you a lot of info for now. Keep me posted and if you have any other questions feel free to ask.
 
#3 ·
If you replace your O2 sensors, be sure to only use NTK/NGK brand as they are usual the OEM one Ma puts in. I have seen on many Mopar web boards that Bosche has a high failure rate.

Run a can of Seafoam thru you gas. I have had and seen many good results form it's use for O2 and Cat cleaning.
 
#4 ·
Yes! I saw and heard that too. So if it is the O2 sensor I'll go with OEM ones.
And as for the Seafoam... I cannot get that stuff anywhere here. The closest one I found was on eBay from UK. Crappy country... But I'll try that later.

P0430 - Catalyst Effeciency BANK 2 You will have one O2 sensor before (Upstream) the catalytic converter and one O2 sensor after (Downstream) the catalytic converter. Any of the 4 O2 sensors can cause this code to set.

This code can be set due to a number of things. Do you have any exhaust leaks (These trucks are very common for exhaust manifold leaks due to broken studs), misfires or any other mechanical issues with the engine that you're aware of? When is the last time you changed the spark plugs?

It can be caused by O2 sensor wiring, connections, Open circuits, shorting to ground, shorting to voltage, etc.

It can also be caused by aged or failed O2 sensors. The upstream O2 sensors tend to carbon up over time and the downstream O2 sensor will stay relatively cleaner after the Cat. These trucks have 4 O2 sensors (2 on each cylinder bank), 2 upstream and 2 downstream. It is recommended that they all be replaced at the same time if you determine that an O2 sensor is at fault. By replacing one 02 sensor out of 3, the new O2 sensor may read slightly different voltage due to being clean and the others carboned and throw the code also (According to Dodge Specs).

Worst case scenario if everything else checks out is a failed catalytic converter. You should be able to inspect it with a flash light after removing the exhaust down pipe from the exhaust manifold. It should have nice white honeycomb and no dents, cracks or holes/melting.

If your engine has been running good mechanically, ie not dumping fuel/misfiring, damaged by impact, your catalytic converter should be fine.

I've given you a lot of info for now. Keep me posted and if you have any other questions feel free to ask.
I replaced the spark plugs about 300 miles ago. I got the truck from an auction so I'm changing bit by bit anything that malfunctions. I also cleaned the throttle body. I did a post on how it was before and after (was very filthy). The truck was stalling when I shifted from D to R, so cleaning the TB and new set of Spark Plugs did the trick. The engine works fine now. It accelerates like it should, well I think it works well since I have nothing to compare it with.

I'd like to check the exhaust manifold. I haven't find a "tutorial" on how to do it but I'll find it :) if you have a link, I'd more than happy to check it out. Maybe the gasket got damaged or wore off...

I'm doing everything myself on the truck because local shops... well I don't trust them. Had pretty upsetting experience with few that are close to me so I'm asking a lot of questions.

I will try to do the "smoke test" to see if there are any leaks in the intake system. It doesn't seem it has any but I'll try.

Many thanks for your help! Should I post any images for a visual guidance?
 
#5 ·
With that many miles your O2 sensors are likely worn out as. Do all 4 and use the OEM brand as others have stated, it matters. Run Seafoam, again like others have stated awesome stuff. FYI I also got that code using a can of Chevron injector cleaner. After I refilled the tank and cleared the code it never came back, so these maybe very sensitive to fuel quality too.
 
#7 ·
I use the 95 octane fuel... That's the lowest around here, next one is 98 oct.
Will try the seafoam!!

To check for Exhaust leaks, it's mostly audible... you can hear them, especially if it's an exhaust manifold/gasket/broken studs. When you cold start the engine, you can audibly hear a "Chuffing" sound coming from either or both sides of the engine at the exhaust manifold(s). It's very common for these engines. Traditionally the "Chuffing" sound will go away as the engine warms up and metallic components expand, lessening or closing the gap, from which exhaust is escaping. There should be videos on YouTube showing Exhaust leak symptoms. A large enough exhaust leak can cause the code you're experiencing. I'm also inclined to agree with 09itsmine, with that many miles your O2 sensors are probably partially plugged/blocked by now. Catalytic converters DO wear out over time, usually caused to improper engine maintenance or mechanical failures leading to catalytic converter damage but typically they last for the life of the vehicle. The only way to tell for sure is to disconnect the exhaust pipes at the exhaust manifolds and visually inspect the catalytic converter for damage, holes, dents melting, etc. O2 sensors are not all that expensive and are a common wear item over time, especially at your mileage. I would inspect the exhaust for leaks, inspect the O2 sensor harness(s) and replace the O2 sensors before worrying too much about the Cat.

If you'd like to for peace of mind inspect the cat(s), you may want to do that as well.
I did a cold start and checked for noises.... Didn't hear anything. Did that twice.
I saw on youtube guys do an air&soap test for the exhaust, so I will try that one.
I cannot say that the truck was taken care off by the previous owner so maybe the CAT is damaged but no rattling sound coming from there.

I will keep you updated for the advice. It will take me few weeks but I'll get it done.
THanks for the guidance!
 
#8 ·
Don't confuse octane rating with quality of fuel. You could have bad fuel with a high octane label. Is this a US/CAN market truck that was exported there or was it originally sold for your market? I ask because it may have a different factory tune if it was originally sold for your market than what is used in US/CAN. If it was originally sold for your market what does the owners manual say for fuel octane rating?
 
#9 ·
I bought the truck off an auctions so there was no manual what so ever...
It is a US truck that I imported to Estonia.
I only fill up the truck with quality fuel. I mean, I only go to large chain gas stations that sell fuel after government inspection. Well, at least they say that...
I still didn't have a chance to go deeper on the truck. I've read on other forums also and many say that O2 sensors with high mileage do go bag, so I'll order a set of four and see if I will get the code after that.
 
#15 ·
I'm on my, like, 10th or 15th gas tank and the code has not come up.
I guess the old fuel was mixed with new fuel and it took a while to get it out from the gas tank. I got the truck from an auction and I have no clue what they put in it (had like 3-4 gallons).

I have a question, is there a way to check if I have the broken bolts without actually tearing whole thing apart? Can I try to tighten the bolts to see if they spin freely - means broken?
 
#17 ·
I have code come up again. Now I have P0420 and P0430.
I just got from underneath my truck and driver side heat shield is missing but all bolts on all side are there. I didn't notice any dark halos around the exhaust manifolds.
The bolts were replaced before. The gaskets seem to be relatively new and I saw grinder marks on the heat shield.
The codes came up when I was driving on an uneven road (had to drive like 10 yards).
Where should I look next? Would replacing O2 sensors be on my list or there could be something else?
 
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