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"P0420 Code: Meaning, Causes & How To Fix It | Mechanic Base
Mar 17, 2023The P0420 code indicates that the ECM has detected underperformance of the catalytic converter's efficiency on Bank 1. It can be caused by a faulty catalyst, or it can be a false alarm caused by a faulty O2 sensor. The engine control module (ECM) uses two O2 sensors, one in front, and one behind the catalytic converter to measure its efficiency."
I wonder why the owner provided a new expensive cat converter.......
Far as I can help, I own a TDI
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casual notes from the underground:There are some "experts" out there that in reality don't have a clue as to what they are doing.
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