I/M Catalyst System Set Procedure
INSPECTION/MAINTENANCE (I/M) CATALYST SYSTEM SET PROCEDUREDESCRIPTION
The purpose of this test is to satisfy the enable criteria necessary to execute inspection/maintenance (I/M) readiness diagnostics for the catalyst system. The test may be used to set the I/M System Status indicators to YES. The I/M System Status display on the scan tool provides an indication of whether the control module has completed the required tests. The I/M System Status does not indicate that the tests have passed or failed. When all of the diagnostics for a specific system have run and passed, the I/M System Status will update to YES. If a test for a specific system has failed, the I/M System Status will update to YES, indicating a determination was made even if all of the other tests for that system have not run.
CONDITIONS FOR RUNNING
- DTCs P0421 and P0431 are not set.
- The engine load is between 20-45 percent.
- The manifold absolute pressure (MAP) sensor variation is less than 6 kPa.
- The catalytic temperature is more than 350°C (662°F).
- The engine is in Closed Loop fuel control.
- The engine speed is between 1,000-2,120 RPM.
DIAGNOSTIC AIDS
The control module runs a calibrated number of catalyst tests per trip until the Catalyst System Status updates to YES. If the status does not update, the test outlined in this procedure can be repeated until the I/M System Status updates to YES.
If there is an impending failure, the system may require more time to run the diagnostic than was allotted in the set procedure. If the test does not run after numerous attempts and no DTC is set, review the appropriate scan tool data list and the service information for an indication of why the test does not complete. Some tests may abort due to changes in the conditions while the test is running. For example, changes in engine load such as a cooling fan or A/C compressor clutch turning ON may cause the test to abort.
TEST
