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Home >> Pontiac >> 2001 >> Sunfire L4-2.2L VIN 4 >> Repair and Diagnosis >> Relays and Modules >> Relays and Modules - Powertrain Management >> Relays and Modules - Computers and Control Systems >> Engine Control Module >> Description and Operation >> Powertrain Control Module (PCM) >> Oxygen Sensor Diagnosis
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Oxygen Sensor Diagnosis

Diagnose the fuel control Oxygen Sensors (O2S) for the following conditions:
^ A slow response
^ Response time, time to switch R/L or L/R
^ An inactive signal, output steady at bias voltage-approximately 450 mV
^ A signal fixed high
^ A signal fixed low

Diagnose the catalyst monitor Heated Oxygen Sensors (HO2S) 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, output steady at approximately 438 mV