Catalytic converter Conversion error 29f4

mapleleaf1773 · 06-16-2021, 12:29 PM

2011 328i XDrive N52

So for the past few months I have had two error that seem to be related. Code "29f4" catalytic converter conversion bank 1 low efficiency and I always get this second code with it "2f4a" interface EWS-DME .

When I first purchased my 328, I took it to the dealer so get a overall check on the car. Of course they came back with a few things here and there and I have taken care of all of those myself. The dealer wanted to stick a scope down the 02 (bank 1) sensor to see if its clogged but I did not do that.

I've replaced both my front O2 sensors and thought of replacing the rear but the O2 graphs looks correct. I even got a 2nd opinion at my trusted local shop (good people). Always possible the downstream 02 sensors are not operating correctly, but not likely.

Unfortunately I am thinking clogged cat (bank 1). I have replaced all plugs and coils. Replaced the Valve cover and all the gaskets and the battery. I do not think it is fuel injector related. The car runs smooth. No rattle in the cats either - by smacking them.

And if it is a clogged cat, I am thinking to go catless downpipes and a tune later to get rid of the error that will follow using them. If I go this route I do not know what downpipes to get. Its an xdrive so I've read the pipes are slightly different than a rwd 328, maybe not?

Or I could get another cat and put it on, but who knows how long bank 2 will last.

In any case, I am just trying to figure my next steps. Any idea's or suggestions would be greatly appreciated.

E92_William · 06-16-2021, 07:56 PM

Well if that was me I'd grab a used sensor from a junkyard car and put it on and see if anything changes or if you're feeling generous, a new one. My car is a 328xi and my headers were supposedly for a rwd car and they fit perfect and all lined up, the stock cats are so bulky that the headers would fit regardless since there's so much room without them, pretty sure the stock exhaust manifolds are the same part number for xi and rwd because I triple checked that.

mapleleaf1773 · 06-16-2021, 10:09 PM

Yea I guess changing the rear O2 sensor (bank 1) would be the best idea.

Where would I find catless headers for my car if you don't mind me asking? You have those part numbers by chance?

Sorry this would be my first time changing headers, kinda worried about getting into it and then something goes wrong or doesn't fit ya know.

06-16-2021, 12:29 PM	#1
mapleleaf1773 First Lieutenant 418 Rep 411 Posts Drives: 2011 BMW 328i XDrive Join Date: Jan 2021 Location: West Virginia iTrader: (0) Garage List 2011 BMW 328i XDrive [0.00]	Catalytic converter Conversion error 29f4 2011 328i XDrive N52 So for the past few months I have had two error that seem to be related. Code "29f4" catalytic converter conversion bank 1 low efficiency and I always get this second code with it "2f4a" interface EWS-DME . When I first purchased my 328, I took it to the dealer so get a overall check on the car. Of course they came back with a few things here and there and I have taken care of all of those myself. The dealer wanted to stick a scope down the 02 (bank 1) sensor to see if its clogged but I did not do that. I've replaced both my front O2 sensors and thought of replacing the rear but the O2 graphs looks correct. I even got a 2nd opinion at my trusted local shop (good people). Always possible the downstream 02 sensors are not operating correctly, but not likely. Unfortunately I am thinking clogged cat (bank 1). I have replaced all plugs and coils. Replaced the Valve cover and all the gaskets and the battery. I do not think it is fuel injector related. The car runs smooth. No rattle in the cats either - by smacking them. And if it is a clogged cat, I am thinking to go catless downpipes and a tune later to get rid of the error that will follow using them. If I go this route I do not know what downpipes to get. Its an xdrive so I've read the pipes are slightly different than a rwd 328, maybe not? Or I could get another cat and put it on, but who knows how long bank 2 will last. In any case, I am just trying to figure my next steps. Any idea's or suggestions would be greatly appreciated. Last edited by mapleleaf1773; 06-16-2021 at 05:20 PM..
	Appreciate 0 Tweet Quote

06-16-2021, 07:56 PM	#2
E92_William Captain 1306 Rep 852 Posts Drives: 2008 BMW 328xi Join Date: Apr 2021 Location: South Florida iTrader: (0)	Well if that was me I'd grab a used sensor from a junkyard car and put it on and see if anything changes or if you're feeling generous, a new one. My car is a 328xi and my headers were supposedly for a rwd car and they fit perfect and all lined up, the stock cats are so bulky that the headers would fit regardless since there's so much room without them, pretty sure the stock exhaust manifolds are the same part number for xi and rwd because I triple checked that. __________________ Airplane Mechanic BMW Masochist
	Appreciate 0 Quote

06-16-2021, 10:09 PM	#3
mapleleaf1773 First Lieutenant 418 Rep 411 Posts Drives: 2011 BMW 328i XDrive Join Date: Jan 2021 Location: West Virginia iTrader: (0) Garage List 2011 BMW 328i XDrive [0.00]	Yea I guess changing the rear O2 sensor (bank 1) would be the best idea. Where would I find catless headers for my car if you don't mind me asking? You have those part numbers by chance? Sorry this would be my first time changing headers, kinda worried about getting into it and then something goes wrong or doesn't fit ya know.
	Appreciate 0 Quote