Code Enable Criteria

NOTE: HO2S 2 is located behind catalytic converter.

DTC P0137 or P0138 is not set.
Intake Air Temperature (IAT) at start-up is less than 113°F (45°C).
Engine Coolant Temperature (ECT) is less than 104°F (40°C).
IAT and ECT are within 50°F (10°C) of each other at start-up.
System voltage is 10-18 volts.
Average mass airflow is less than 25 grams/sec.