Oxygen Sensor Diagnosis

HEATED OXYGEN SENSOR (HO2S 1)
The Fuel Control Heated Oxygen Sensor (HO2S 1) is diagnosed for the following conditions:

^ Slow Response
^ Inactive Signal (output steady at bias voltage - approx. 450mV)
^ Signal Fixed High
^ Signal Fixed Low

CATALYST MONITOR HEATED OXYGEN SENSOR (HO2S 2)
The Catalyst Monitor Heated Oxygen Sensor (HO2S 2) is diagnosed for the following functions:

^ Heater Performance (time to activity on cold start)
^ Signal fixed low during steady state conditions or power enrichment (hard acceleration when a rich mixture should be indicated)
^ Signal fixed high during steady state conditions or decel fuel mode (deceleration when a lean mixture should be indicated)
^ Inactive Sensor