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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1539 (Engine Controls (Troubleshooting & Diagnosis) -- 5.7L) >> Troubleshooting >> Inspection/Maintenance (I/M) AIR System Set Procedure >> Diagnostic Aids

Diagnostic Aids

WARNING: This page is about a different car, the 2004 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

The AIR pump generally operates once per ignition cycle, usually upon initial start up before the engine goes into Closed Loop Fuel Control. Some systems will perform a Passive Diagnostic Test at this time. The Active Diagnostic Test is performed after the engine goes into Closed Loop Fuel Control. On vehicles that perform a Passive Test, the Active Test will only run if the Passive Test fails or is indeterminate. The Active Test may not run if the Passive Test passes.

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.

Inspection/Maintenance (I/M) AIR System Set Procedure

Step Action Yes No
1 Did you perform the Inspection/Maintenance (I/M) System Check? Go to Step 2  Go to Inspection/Maintenance (I/M) System Check 
2
  1. Ensure the vehicle is within the Conditions for Running specified in the supporting text.
  2. Turn OFF all of the accessories, including the A/C and the blower fan.
  3. Start the engine. Allow the engine to idle for 2 minutes.
    4. CAUTION: Refer to Road Test Caution in Cautions and Notices.
    IMPORTANT: In order for the Active Test to run, the vehicle must operate in the following conditions:
  4. Acceleration at part throttle to 72 km/h (45 mph) with this speed maintained for 3 minutes or until the I/M System Status indicator updates to YES.
  5. Review the I/M System Status display with a scan tool.
Did the AIR 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 Diagnostic Trouble Code (DTC) List Go to Step 4 
4
  1. Refer to the Inspection/Maintenance (I/M) System DTC Table  to determine which DTCs are required to run in order to complete this test.
  2. Observe the Not Ran Since Code Cleared display with a scan tool.
  3. Determine which of the DTCs required for a YES status has not run.
  4. Enter the DTC number in the Specific DTC menu of the scan tool.
  5. Operate the vehicle within the Conditions for Running the DTC, located in the supporting text for the diagnostic table of the DTC.
  6. Repeat the procedure until the scan tool indicates the diagnostic test has run.
  7. Repeat steps 4-6 for any additional required DTCs that have not run.
  8. Observe the I/M System Status display with a scan tool.
Did the AIR 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?		 Go to Diagnostic Trouble Code (DTC) List System OK
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