P420 Check engine code

teko360x · 05-16-2023, 10:49 PM

I have a 2013 BMW 335i Xdrive

I am getting the P420 error bank 1 runnning below threshold

modifications on the car :
- Vibrant resonator
- Miestercragt GT catback exhaust
- BMS intake

No other mods on the car. I am getting this error code and not sure if the o2 sensor is the issue or the Catalytic converter is the issue? and if I intall a o2 sensor spacer to the rear 02 sensor will it resolve the issue ?

please let me know where should I start the diagnostics

thejeremyman9 · 05-17-2023, 10:09 AM

Is that the catalyst efficiency below threshold error? No other codes showing?

Do not install a spacer that wont solve anything

n55david · 05-17-2023, 02:59 PM

Either cat is failing or you have a bad 02. It's one or the other and there isn't any way to know without replacing stuff.

teko360x · 05-27-2023, 12:25 AM

I am going to attache the screenshot of the error code I get from my ODB 2

05-16-2023, 10:49 PM	#1
teko360x Registered 0 Rep 4 Posts Drives: 335 Join Date: May 2023 Location: ottawa iTrader: (0)	P420 Check engine code I have a 2013 BMW 335i Xdrive I am getting the P420 error bank 1 runnning below threshold modifications on the car : - Vibrant resonator - Miestercragt GT catback exhaust - BMS intake No other mods on the car. I am getting this error code and not sure if the o2 sensor is the issue or the Catalytic converter is the issue? and if I intall a o2 sensor spacer to the rear 02 sensor will it resolve the issue ? please let me know where should I start the diagnostics
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05-17-2023, 10:09 AM	#2
thejeremyman9 Major General 4374 Rep 7,622 Posts Drives: 2015 BMW 335i Join Date: May 2019 Location: Cali iTrader: (0)	Is that the catalyst efficiency below threshold error? No other codes showing? Do not install a spacer that wont solve anything
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05-17-2023, 02:59 PM	#3
n55david Check out my Youtube @n55david! 1297 Rep 3,536 Posts Drives: 2017 m240i, 2015 X3 x35i Join Date: Aug 2018 Location: Michigan USA iTrader: (0) Garage List 2017 m240i xDrive [0.00] 2015 X3 x35i [0.00] 2015 335i xdrive [0.00]	Either cat is failing or you have a bad 02. It's one or the other and there isn't any way to know without replacing stuff. __________________ 2017 m240i xDrive 10.67@132.32mph w/bm3 2015 335i xDrive 10.95@124.99mph w/bm3 - SOLD 2015 X3 x35i pwg 12.96 catless w/bm3 stage 2 93 ots IG: @n55david For pics and updates! Youtube: @ n55david For videos or Racing etc
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05-27-2023, 12:25 AM	#4
teko360x Registered 0 Rep 4 Posts Drives: 335 Join Date: May 2023 Location: ottawa iTrader: (0)	I am going to attache the screenshot of the error code I get from my ODB 2 Attached Images
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