Test Description

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

1. 1  - Perform the I/M System Check before performing this test. Failure to do so may result in difficulty updating the status to YES.
2. 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.

   The PCM considers the engine to be cold if the following conditions are met:

   • ECT sensor parameter is less than 86°F (30°C).
   • ECT and IAT are within 7°F of each other at start up.

3. 3  - This step runs the EVAP, AIR and the 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.
4. 4  - This step is to run the EGR tests. The EGR Tests are run during a gradual deceleration with a closed throttle. The vehicle speed is required to maintain a high, steady Manifold Absolute Pressure (MAP) signal.
5. 5  - 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.
6. 6  - Perform the individual system test for any of the systems that do not update to YES.
7. 7  - The I/M system status only reports on whether or not a diagnostic has run, not the outcome of the test. If any emission related DTC sets after the tests are complete, the DTC will require diagnosis.