DTC P0141: Ho2S Bank 1 Sensor 2 - Heater Performance: Description

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

The Heated Oxygen Sensor (HO2S) heater is a device used in order to reduce the time that the sensor takes to go active. The HO2S bank 1 sensor 2 heater helps to maintain the sensor at the proper temperature for catalyst testing, and additional adjustments to fuel trim. The HO2S heater receives power through a fused ignition circuit. The Powertrain Control Module (PCM) turns the heater ON and OFF using a low side driver Output Driver Module (ODM) located within the PCM. The PCM will test the heater only after a cold start. The PCM determines a cold start based on the difference between the Engine Coolant Temperature (ECT) at the last key OFF, and the ECT at the current key ON. When the HO2S voltage indicates a sufficiently active sensor, the PCM looks at how much time has elapsed since start-up. If the PCM determines that too much time was required for the sensor to become active, this DTC will set. The amount of time for the sensor to reach operating temperature is based on the ECT at start-up and the average Mass Air Flow (MAF) since start-up (more air flow and/or higher start-up ECT results in a shorter time to sensor activity).