Do you find yourself troubled condemning a catalytic converter simply due to dreaded stored DTCs P0420 and/or P0430? Welcome to the club!
Many technicians today still don’t quite grasp the functionality of the catalytic converter. In this episode of The Trainer, join Motor Age Magazine’s Technical Editor, Brandon Steckler as he demystifies the catalytic converter’s functionality.
Because the catalytic converter functions as it does due to a chemical reaction, it has certain requirements to function properly. The feed gas that leaves the internal combustion engine drives its performance.
A catalytic converter has two main areas that operate to chemically convert the harmful post-combustion gases (Hydrocarbon, Carbon monoxide, and Oxides of nitrogen) into non-poisonous gases (Carbon dioxide, nitrogen) and water (H2O2). These areas are the reduction section and the oxidation section. Each of these contains different combinations of precious metals that will react to rich and lean feed gas mixtures differently.
The catalytic converter’s job is to store oxygen and use that oxygen for the chemical reaction. This means very little oxygen should leave the catalytic converter if it is functioning properly. The PCM monitors the signal from the rear (post-CAT) oxygen sensor to determine the CAT's ability to store and use oxygen. Currently, there are two ways the PCM can determine this:
· Switched-Index Ratio
· Oxygen Storage Capacity (OSC)
As diagnosticians, we can learn to leverage graphed scan tool data to make diagnostic decisions right from the driver’s seat! Follow Brandon as he carries out this simple and easy-to-perform process using global scan tool data.
Brandon will demonstrate the operation of a known-good catalyst, using both the OSC test and the Switched-Index Ratio test. Pull up a chair, stay tuned, and learn the techniques that made Brandon successful and efficient as a driveability diagnostician in the trenches!
About the Author
Brandon Steckler
Technical Editor | Motor Age
Brandon began his career in Northampton County Community College in Bethlehem, Pennsylvania, where he was a student of GM’s Automotive Service Educational program. In 2001, he graduated top of his class and earned the GM Leadership award for his efforts. He later began working as a technician at a Saturn dealership in Reading, Pennsylvania, where he quickly attained Master Technician status. He later transitioned to working with Hondas, where he aggressively worked to attain another Master Technician status.
Always having a passion for a full understanding of system/component functionality, he rapidly earned a reputation for deciphering strange failures at an efficient pace and became known as an information specialist among the staff and peers at the dealership. In search of new challenges, he transitioned away from the dealership and to the independent world, where he specialized in diagnostics and driveability.
Today, he is an instructor with both Carquest Technical Institute and Worldpac Training Institute. Along with beta testing for Automotive Test Solutions, he develops curriculum/submits case studies for educational purposes. Through Steckler Automotive Technical Services, LLC., Brandon also provides telephone and live technical support, as well as private training, for technicians all across the world.
Brandon holds ASE certifications A1-A9 as well as C1 (Service Consultant). He is certified as an Advanced Level Specialist in L1 (Advanced Engine Performance), L2 (Advanced Diesel Engine Performance), L3 (Hybrid/EV Specialist), L4 (ADAS) and xEV-Level 2 (Technician electrical safety).
He contributes weekly to Facebook automotive chat groups, has authored several books and classes, and truly enjoys traveling across the globe to help other technicians attain a level of understanding that will serve them well throughout their careers.