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The previous CEL came on in cooler weather and always went away when warm.
That would make sense since it's the sensor's heater that was causing the cel... In cold weather then o2 sensor would not get hot enough just with the exhaust gases fast enough to not throw a code.... But in the summer time... It would happen much faster... So no codes.
 

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Mine was not for the heater, it was cat efficiency, which does nearly the same thing. The O2 sensor reads the O2 level, the lower the O2, the higher (in general) temp the cat is. The O2 heater circuit is measured in resistance (as far as I know).
 
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The O2 heater circuit is measured in resistance (as far as I know).
I am not an electrical engineer..but I did read this recently:
 

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2004 2.8 V6 B5.5, now a 2012 CC GT
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I had this CEL on my V6 on both banks (p0420 and P0421). It passed state emissions inspection so i spaced out the O2 sensors and never had the CEL again. When the car starts the SAIP runs for 90 seconds (when cold). The ECU checks the readings on the rear O2 sensors to check the CAT efficiency. You can check the voltage to the sensor where they mount the electrical connectors on the firewall - you can even do a resistance check of the sensor there to see if one is bad.
 

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Discussion Starter #25
Replace your downstream sensor
I replaced the sensor and after the 141 code I got a 161 code, replaced the other sensor and code (161) came back today ....



Sent from my iPhone using Tapatalk
 

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I replaced the sensor and after the 141 code I got a 161 code, replaced the other sensor and code (161) came back today ....



Sent from my iPhone using Tapatalk
Hopefully you don't live in a CARB state.... Sounds like it's about cat o'clock? It's all I got.
 
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