Code Enable Criteria

• Engine speed is 1500-3200 RPM.
• Loop status is closed.
• Calculated airflow is 7-25 grams per second.
• No CMP, CKP, ECT, EGR, EVAP purge solenoid, fuel trim, IAT, MAP, misfire, or TP sensor DTCs are set.

DTC sets when average response time of lean-to-rich switch is greater than 140 milliseconds for greater than 100 seconds, or average response time of rich-to-lean switch is greater than 225 milliseconds for greater than 100 seconds.