DTC P0141: Ho2S 2 Heater Performance - Sensor 2 (Regal): Description

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2002 Pontiac Grand Prix, 2002 Pontiac Bonneville, 2002 Chevrolet Monte Carlo, 2002 Chevrolet Impala, and 2002 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.

Heated Oxygen Sensors (HO2S) are used in order to minimize the time required for the closed loop fuel control operation, and in order to allow accurate catalyst monitoring. The HO2S heater greatly decreases the time required for the fuel control sensor HO2S 1 to become active. The HO2S heater is required by the catalyst monitor sensor HO2S 2 to maintain a sufficiently high temperature. This allows accurate exhaust oxygen content readings further from the engine.

The Powertrain Control Module (PCM) will run the heater test only after a cold start, as determined by the Engine Coolant Temperature (ECT) and the Intake Air Temperature (IAT) at the time of start-up, and only once during an ignition cycle. When the engine is started, the PCM will monitor the HO2S voltage. When the bank HO2S voltage indicates a sufficiently active sensor, the PCM looks at how much time has elapsed since start-up. The time necessary for the HO2S to reach the operating temperature is based on the ECT at start-up and the average Mass Airflow (MAF) since start-up. More total airflow or a higher start-up ECT equals a shorter time to HO2S activity. If the PCM determines that too much time was required for the HO2S 2 to become active, DTC P0141 will set.