DTC P0141: Ho2S 2 Heater Circuit (SOHC): Description

WARNING: This page is about a different car, the 2002 Pontiac Sunfire, 2002 Pontiac Grand Am, 2002 Oldsmobile Alero, and 2002 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.

In order to control emissions, a Three-Way Catalytic (TWC) converter converts any harmful exhaust emissions into harmless water vapor and carbon dioxide.

The Powertrain Control Module (PCM) has the capability to monitor this process by using a rear Heated Oxygen Sensor (HO2S) 2. The HO2S 2, located in the exhaust stream past the TWC converter, produces an output signal which indicates the storage capacity of the catalyst. This in turn indicates the catalysts ability to convert the exhaust emissions effectively. If the catalyst is functioning properly, the HO2S 2 signal will be far less active than the signal produced by the front HO2S 1.

Obstruction of the air reference and degraded HO2S 2 performance can result from any attempt to repair the noted conditions. The HO2S 2 must have a clean air reference in order for the HO2S 2 to function properly. This clean air reference is obtained by way of the HO2S 2 wires.