View Single Post
Old 03-31-2023, 10:23 AM   #14 (permalink)
Somewhat crazed
Piotrsko's Avatar
Join Date: Sep 2013
Location: 1826 miles WSW of Normal
Posts: 4,024
Thanks: 460
Thanked 1,096 Times in 967 Posts
"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
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.
  Reply With Quote
The Following User Says Thank You to Piotrsko For This Useful Post:
V6MustangFTW (03-31-2023)