Catalyst Monitoring

A sub-oxygen sensor (S2) placed downstream, at the outlet of the catalytic converter, is monitored for switching frequency and compared to the switching frequency of the main oxygen sensor (S1), placed upstream of the catalyst. The oxidation efficiency of the catalyst can be determined by comparing the switching frequency of these two sensors. As the catalyst conversion efficiency declines, the switching frequency of sensor 2 increases, approaching that of sensor 1. In addition to being used for diagnostics, sensor 2 also assists in maintaining optimum fuel control when the catalyst begins to degrade.

Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

Don't pay hundreds of dollars to find out what is wrong with your car. This book is dedicated to helping the do it yourself home and independent technician understand and use OBD-II technology to diagnose and repair their own vehicles.

Get My Free Ebook


Post a comment