P0430 again and again and again

[swathdiver]

My Magnaflow cats are doing just fine after 54K miles.

 

[BG1988]

2007 Tahoe PPV 5.3 w/250k miles

Here it is, the infamous P0430 Catalyst System Efficiency Below Threshold Bank 2

I know I know, it's been posted a million times before. Mine pops up and clears itself quite often. I'll get it read and have them clear it and he says after 30 miles it will op up again. But then it clears itself. Just looking to resolve it once and for all.

I have read so much in regard to getting this resolved but am not sure where I should start. Between the coolant to sensors I'm kinda lost.
Who would've thought the coolant could have something to do with Catalyst system?

Oh and it runs and drives fine, no issues at all.

Thoughts opinions suggestions?
All info is much appreciated
Thanks

P0430 is bank 2 are the O2 sensors slow to respond with a DFCO? mine is check engine with P0430 as well while ending a DFCO event my Short term fuel trim spikes to 34.5+( Bank 1 and Bank 2 ) which is the "MAX lean condition" (it's just pumping air?) there is also a mild lag time when exiting a DFCO, this could also be a Fuel pump issue...

if you have an OBD reader you can see if the voltages are "following" each other then the Cat may need replacement...

 

[992dr]

P0430 is bank 2 are the O2 sensors slow to respond with a DFCO? mine is check engine with P0430 as well while ending a DFCO event my Short term fuel trim spikes to 34.5+( Bank 1 and Bank 2 ) which is the "MAX lean condition" (it's just pumping air?) there is also a mild lag time when exiting a DFCO, this could also be a Fuel pump issue...

if you have an OBD reader you can see if the voltages are "following" each other then the Cat may need replacement...

Sorry, I'm not sure what DFCO means or stands for. Google says deceleration fuel cut off. Is this correct?

If it could be read on a scanner, hopefully I will find out tomorrow morning as I have an appointment with my mechanic.

Gotta be honest, I know nothing about tuning or anything electrical. I'll bring it up to Vic in the morning and post an update in the afternoon.

Appreciate your input

 

[George B]

Sorry, I'm not sure what DFCO means or stands for. Google says deceleration fuel cut off. Is this correct?

If it could be read on a scanner, hopefully I will find out tomorrow morning as I have an appointment with my mechanic.

Gotta be honest, I know nothing about tuning or anything electrical. I'll bring it up to Vic in the morning and post an update in the afternoon.

Appreciate your input

Don’t get sucked into overthinking this. It is going to be a bad cat…

 

[992dr]

Don’t get sucked into overthinking this. It is going to be a bad cat…

I'm trying not to over think this haha
That's what I'm expecting/hoping

 

[BG1988]

I'm trying not to over think this haha
That's what I'm expecting/hoping

i'm betting it's not a Bad Cat the P0430 i'm getting is from inverse reading for the O2 sensor sensor 1 reading high(i.e 0.835v while sensor 2 is reading 0.135v that means the sensor is faulty if i;m getting inverse numbers...

it's only faulty Catalytic converter if sensor 2 is "following" sensor 1 that is a clear confirmed indication the cat has failed.....

also typically you get P0420 before you would get a P0430 code (or both the p0420 and p0430) as bank 1 typically fails first on most cars...

 

[992dr]

I got the results. Everything looks good. No misfires or any stored in the history, fuel trims look great and O2 sensors are all in check. He was pretty impressed with how well is was running and said it's running almost perfect.
We didn't do a cat pressure test but he did mention with 250k miles on the clock and them being original, it wouldn't be bad idea. That along with some O2 sensors and everything should be good to go.

i'm betting it's not a Bad Cat the P0430 i'm getting is from inverse reading for the O2 sensor sensor 1 reading high(i.e 0.835v while sensor 2 is reading 0.135v that means the sensor is faulty if i;m getting inverse numbers...

it's only faulty Catalytic converter if sensor 2 is "following" sensor 1 that is a clear confirmed indication the cat has failed.....

also typically you get P0420 before you would get a P0430 code (or both the p0420 and p0430) as bank 1 typically fails first on most cars...

I appreciate your info, it's all making more sense with every new comment.

Crazy how much you learn from members and techs haha. I certainly do appreciate the help from everyone.

So, the big question is - Would I be out of my mind for replacing my cats and O2s?


Again thanks for all the help

 

[treehan77]

Results of what? What did you do?

 

[992dr]

Brought it to my mechanic to throw on the scanner to see what was going on with my 0430
I guess I didn't do anything, he pushed buttons.

 

[treehan77]

So you still have the code then?