Monitored & Set Conditions

1/2 Heated Oxygen Sensor (HO2S) heater operation is monitored after ignition is turned off and engine cools down. DTC will be stored in Powertrain Control Module (PCM) memory if no downstream oxygen sensor signal is received when PCM powers up oxygen sensor heater. Possible causes for DTC to set are: intermittent condition, defective downstream oxygen sensor or heater, defective Auto Shutdown (ASD) relay circuit, or defective connectors or wiring.