Test Description

The numbers below refer to the step numbers in the diagnostic test procedure.

1. 1
   
   Make sure you 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 is to run 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.
3. 3
   
   This step runs the EVAP, AIR and oxygen sensor tests. The EVAP test begins once engine coolant reaches a calibrated temperature. The AIR test, if equipped, begins shortly after Closed Loop and indicated speed is achieved. The Oxygen sensor tests begin once engine is at operating temperature, in Closed Loop fuel control, and a calibrated amount of time has elapsed.
4. 4
   
   This step runs the EGR tests. The EGR tests are run during a gradual deceleration with a closed throttle. The vehicle speed is required in order 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 what the outcome of the test was. If any emission related DTC sets after the tests are complete, the DTC will require diagnosis.