K 1500 Truck 4WD V8-5.7L VIN R (1997)
Oxygen Sensor: Testing and Inspection
Heated Oxygen Sensor (HO2S) Testing
Heated Oxygen Sensor (HO2S) Cutaway
The Heated Oxygen Sensors are mounted in the exhaust system where they can monitor the oxygen content of the exhaust gas stream. The oxygen
present in the exhaust gas reacts with the sensor to produce a voltage output. This voltage should constantly fluctuate from approximately 100 mV
(high oxygen content - lean mixture) to 900 mV (low oxygen content - rich mixture). The heated oxygen sensor voltage can be monitored with a
scan tool. By monitoring the voltage output of the oxygen sensor, the VCM calculates what fuel mixture command to give to the injectors (lean
mixture - low HO2S voltage = rich command, rich mixture - high HO2S voltage = lean command).
When the VCM detects an HO2S signal circuit that is low, the VCM will set the following Diagnostic Trouble Code (DTC)s:
