Oxygen Sensor: Testing and Inspection

HEATED OXYGEN SENSOR (HO2S)

INSPECTION

FUNCTION AND OPERATION PRINCIPLE
Heated Oxygen Sensor (HO2S) consists of zirconium and alumina and is installed on upstream and downstream of the Manifold Catalyst Converter (MCC). After it compares oxygen consistency of the atmosphere with the exhaust gas, it transfers the oxygen consistency of the exhaust gas to the ECM. In order that this sensor normally operates, the temperature of the sensor tip is higher than 370 °C (698 °F). So it has a heater which is controlled by the ECM duty signal. When the exhaust gas temperature is lower than the specified value, the heater warms the sensor tip.

SPECIFICATION

HO2S [Bank 1/ Sensor 1] - Specification:

HO2S [Bank 1/ Sensor 2] - Specification:

CIRCUIT DIAGRAM

Circuit Diagram:

COMPONENT INSPECTION
1. Disconnect the HO2S connector.
2. Measure resistance between HO2S heater terminals 5 and 6 [B1/S1].
Measure resistance between HO2S heater terminals 3 and 4 [B1/S2].
3. Check that the resistance is within the specification.

Specification : Refer to SPECIFICATION.