Oxygen Sensor Diagnosis

The Fuel Control Heated Oxygen Sensor (HO2S 1) is diagnosed for the following conditions:
^ The Heater Performance (time to activity on cold start)
^ A Slow Response
^ The Response Time (time to switch R/L or L/R)
^ An Inactive Signal
^ A Signal Fixed High
^ A Signal Fixed Low

The Catalyst Monitor Heated Oxygen Sensor (HO2S 2) is diagnosed for the following functions:
^ The Heater Performance (the time to activity on a cold start)
^ The Signal fixed low during steady state conditions or power enrichment (a hard acceleration when a rich mixture should be indicated).
^ The Signal fixed high during steady state conditions or a decel fuel mode (deceleration when a lean mixture should be indicated)
^ An Inactive Sensor (output steady at approx. 438 mV)