The Dreaded P0420
presented in person by Jeff Bly, NAPA Auto Tech Trainer
sponsored by NAPA Autotech
The OBDII generic P0420 code is defined as: Low Catalyst Efficiency –Bank 1. P0420 is one of the most common codes a diagnostics technician will deal with on modern vehicles. This code has been a part of our industry for the last 25 years, since the implementation of OBDII. Yet, most automotive technicians lack a full understanding of all the different circumstances that could cause the Powertrain Control Module to set this code. In this brief, no nonsense, presentation, we will explain modern OBDII fuel control from a catalyst efficiency diagnostics approach. Discover the exact conditions needed to achieve catalytic efficiency at the inlet of the converter. You will learn what to expect, as far as an exact voltages, from the pre & post catalyst oxygen sensors under all normal driving conditions. Discover how to use generic freeze frame data to simulate intermittent code set conditions. Learn how common vehicle reprogramming can come into play while trying to solve this seemingly simple code. This presentation will be mostly designed for automotive service technicians. But, will also be very useful information for service managers & shop owners who want to learn more about real world solutions for this very common catalyst efficiency code.