Check Engine Light: 2C78, 2C7C, 2CA9 -> 29F4, 29F5

Hotter · 09-04-2022, 04:01 AM

Hi, I have had transmission change which has included removing exhaust system (done by mechanic).

Now I got check engine light and codes:
2C78 - DME: Oxygen sensor after catalytic converter 2, signal
2C7C - DME: Oxygen sensor after catalytic converter 2, signal (same code???)
2CA9 - DME: Oxygen sensor heater 2 after catalytic converter: Function

I have tried deleting errors but they return (2C78 returns immediately next time I drive, 2CA9 returns after some time).
Are these error connected with removing exhaust system? What could be wrong?
Does this mean that my Catalytic converter is bad? If they do not impact driving/performance is there a way to disable at least check engine light?

TGTIW · 09-06-2022, 03:19 PM

First and easiest thing to do would be to check the O2 sensors where re-installed / plugged in.

Hotter · 09-17-2022, 07:41 AM

I have tested O2 sensor and it seems it was bad (constantly showing 0.4V). I have replaced it, but now I have other errors...:

29F4 DME: Catalytic-converter conversion
29F5 DME: Catalytic-converter conversion 2

Can both primary CAT's go bad at the same time?
I have removed secondary CAT's does this impact these errors?
Is there an easy way to disable CEL without desoldering instrument cluster LED?

Any other ideas how to get rid of these errors and CEL?
I have read somewhere that MAF-less tune might help?

Hotter · 09-25-2022, 05:00 AM

Any ideas on errors 29F4, 29F5?

I have recorded "Lambda Voltages Before Cat (blue) and After Cat (green) of Both Banks 1 and 2 (two lines each):

At the last peak of "Lambda Voltage Before Cat" (~3.3V) I get Check Engine Light.

Is it possible to verify from this chart that lambda sensors or cats are bad?
Can both cats be bad at same time?
Could it be because of increased power "328i->330i"?

I have an option to go to Inspection next month which will check my exhaust gases and I guess this would verify if my cats are bad?

Hotter · 10-11-2022, 06:05 AM

I have passed emission exhaust gas test, even though results are higher than previous years, but still within norms, so my CAT's might have slight damage, but still working.

How do I get rid of the errors 29F4, 29F5?

Hotter · 10-12-2022, 12:24 AM

Is my only option to buy DME tune (like StageFP) which includes downpipe mod?
Can I run DME tune which includes downpipe mod with CATs installed?

09-04-2022, 04:01 AM	#1
Hotter First Lieutenant 72 Rep 381 Posts Drives: BMW E92 328i -> 330i Join Date: Feb 2018 Location: Lithuania iTrader: (0)	Check Engine Light: 2C78, 2C7C, 2CA9 -> 29F4, 29F5 Hi, I have had transmission change which has included removing exhaust system (done by mechanic). Now I got check engine light and codes: 2C78 - DME: Oxygen sensor after catalytic converter 2, signal 2C7C - DME: Oxygen sensor after catalytic converter 2, signal (same code???) 2CA9 - DME: Oxygen sensor heater 2 after catalytic converter: Function I have tried deleting errors but they return (2C78 returns immediately next time I drive, 2CA9 returns after some time). Are these error connected with removing exhaust system? What could be wrong? Does this mean that my Catalytic converter is bad? If they do not impact driving/performance is there a way to disable at least check engine light? Last edited by Hotter; 09-17-2022 at 07:42 AM..
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09-06-2022, 03:19 PM	#2
TGTIW Second Lieutenant 130 Rep 245 Posts Drives: 2010 328i Join Date: May 2013 Location: Knoxville iTrader: (2)	First and easiest thing to do would be to check the O2 sensors where re-installed / plugged in.
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09-17-2022, 07:41 AM	#3
Hotter First Lieutenant 72 Rep 381 Posts Drives: BMW E92 328i -> 330i Join Date: Feb 2018 Location: Lithuania iTrader: (0)	I have tested O2 sensor and it seems it was bad (constantly showing 0.4V). I have replaced it, but now I have other errors...: 29F4 DME: Catalytic-converter conversion 29F5 DME: Catalytic-converter conversion 2 Can both primary CAT's go bad at the same time? I have removed secondary CAT's does this impact these errors? Is there an easy way to disable CEL without desoldering instrument cluster LED? Any other ideas how to get rid of these errors and CEL? I have read somewhere that MAF-less tune might help?
	Appreciate 0 Quote

09-25-2022, 05:00 AM	#4
Hotter First Lieutenant 72 Rep 381 Posts Drives: BMW E92 328i -> 330i Join Date: Feb 2018 Location: Lithuania iTrader: (0)	Any ideas on errors 29F4, 29F5? I have recorded "Lambda Voltages Before Cat (blue) and After Cat (green) of Both Banks 1 and 2 (two lines each): At the last peak of "Lambda Voltage Before Cat" (~3.3V) I get Check Engine Light. Is it possible to verify from this chart that lambda sensors or cats are bad? Can both cats be bad at same time? Could it be because of increased power "328i->330i"? I have an option to go to Inspection next month which will check my exhaust gases and I guess this would verify if my cats are bad?
	Appreciate 0 Quote

10-11-2022, 06:05 AM	#5
Hotter First Lieutenant 72 Rep 381 Posts Drives: BMW E92 328i -> 330i Join Date: Feb 2018 Location: Lithuania iTrader: (0)	I have passed emission exhaust gas test, even though results are higher than previous years, but still within norms, so my CAT's might have slight damage, but still working. How do I get rid of the errors 29F4, 29F5? Last edited by Hotter; 10-11-2022 at 06:41 AM..
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10-12-2022, 12:24 AM	#6
Hotter First Lieutenant 72 Rep 381 Posts Drives: BMW E92 328i -> 330i Join Date: Feb 2018 Location: Lithuania iTrader: (0)	Is my only option to buy DME tune (like StageFP) which includes downpipe mod? Can I run DME tune which includes downpipe mod with CATs installed?
	Appreciate 0 Quote