Test Description

The numbers below refer to the step numbers in the diagnostic procedures.

1. 2  - This step runs the HO2S heater tests and initiate the EVAP system test.

   Preprogramming the scan tool will reduce the amount of time the oxygen sensor heaters operate while verifying the enable criteria.

2. 3  - This step runs the EVAP, AIR and oxygen sensor tests. The EVAP test begins once the engine coolant reaches a calibrated temperature. The AIR Test, if equipped, begins shortly after closed loop and the indicated speed is achieved. The oxygen sensor tests begin once the engine is at operating temperature, in closed loop fuel control, and a calibrated amount of time has elapsed.
3. 4  - This step runs the catalyst tests. This test runs during the idle period immediately following a cruise period that meets a minimum calibrated RPM and time period.