The purpose of this test is to satisfy the enable criteria necessary to execute 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. 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 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.
• | The engine has been running longer than 10 minutes. |
• | The engine load must be stable. |
• | The idle air control (IAC) position parameter does not change more than 20 counts. |
• | The short term FT is between -23 and +16 percent. |
• | The mass air flow (MAF) is more than 10 g/s. |
• | The catalytic temperature is between 525-675°C (977-1,247°F). |
• | The vehicle speed sensor (VSS) is more than 5 km/h (3 mph). |
• | The barometric pressure (BARO) is more than 75 kPa. |
• | Engine coolant is at operating temperature, 70-125°C (158-257°F). |
• | The intake air temperature (IAT) is between -20 to +80°C (-4 to +176°F). |
• | The engine is in Closed Loop fuel control. |
• | The battery voltage is more than 11 volts. |
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 an A/C compressor clutch turning ON, may cause the test to abort.
Step | Action | Yes | No | ||||
---|---|---|---|---|---|---|---|
1 | Did you perform the Inspection/Maintenance (I/M) System Check? | Go to Step 2 | |||||
2 |
Caution: Refer to Road Test Caution in the Preface section. Important: In order for this test to run, the vehicle must operate in the following conditions:
Did the Catalyst System Status update to YES? | Go to Step 5 | Go to Step 3 | ||||
3 | Observe the DTC Information with a scan tool. Does the scan tool indicate any failed DTCs? | Go to Step 4 | |||||
4 |
Did the Catalyst System Status update to YES? | Go to Step 5 | Go to Diagnostic Aids | ||||
5 | Observe the Emission Related DTC portion of the I/M System Status display with a scan tool. Does the scan tool indicate any Emission Related DTCs set? | System OK |