Circuit Description

WARNING: This page is about a different variant/trim than selected.

The heated oxygen sensor (HO2S) produces a voltage that varies between 100-900 mV under normal operating conditions. The engine control module (ECM) produces a bias voltage on the HO2S signal circuit of 420-480 mV. The reference ground for the sensor is provided through the ECM. The ECM monitors the signal voltage to determine if the exhaust is lean or rich. The oxygen sensor voltage is high when the exhaust is rich, and low when the exhaust is lean. The ECM constantly monitors the HO2S signal during the Closed Loop operation. If the ECM detects an HO2S voltage that stays below a specified value, or if the HO2S calculated resistance is below a specified value, DTC P0137 will set for bank 1 sensor 2, or DTC P0157 will set for bank 2 sensor 2.