Circuit Description

WARNING: This page is about a different car, the 2002 Oldsmobile Intrigue and 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.

The catalyst with the catalytic converter promotes a chemical reaction with oxidizes Hydrocarbons (HC) and Carbon Monoxide (CO) that is present in the exhaust gas. This reaction converts the compounds into harmless water vapor and in carbon dioxide. The catalyst will also convert the Oxides of Nitrogen (NOx) into nitrogen. Powertrain Control Module (PCM) monitors this process via the signal from Heated Oxygen Sensor (HO2S) bank 1 sensor 1. HO2S bank 1 sensor 1 produces an output signal which indicates oxygen storage capacity or the catalyst. Oxygen storage capacity is one method of determining the catalyst's ability to convert exhaust emissions effectively. If catalyst is functioning correctly, HO2S bank 1 sensor 2 will be less active than HO2S bank 1 sensor 1 signal. If PCM detects excess HO2S bank 1 sensor 2 signal activity for an extended period of time, this DTC will set.