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Diagnostic Procedures

  1. If I/M system check has been performed, go to next step. If I/M system check has not been performed, go to INSPECTION/MAINTENANCE SYSTEM CHECK .
  2. Ensure the vehicle is operating within the Conditions for Running. Turn OFF all of the accessories (e.g., A/C, blower fan, etc.). Start and idle engine. Accelerate vehicle at part throttle to 45-55 MPH and operate vehicle within the specified speed for 9 minutes or until the I/M system Status updates to YES. On M/T, either 5 or 6-speed, may require operation in 4th or 5th gear respectively, in order for this test to run. With a scan tool, review the I/M system Status display. Did the HO2S/O2S system Status update to YES? If yes, go to step  5. If no, go to next step.
  3. Using scan tool, observe DTC information. Does the scan tool indicate any failed DTCs? If yes, perform appropriate diagnostic test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, go to next step.
  4. Refer to the Inspection/Maintenance (I/M) System DTC Table to determine which DTCs are required to run in order to complete this test. See INSPECTION/MAINTENANCE SYSTEM DTCS . With a scan tool, observe the Not Ran Since Code Cleared display. Determine which of the DTCs required for a YES status has not run. Enter the DTC number in the Specific DTC menu of the scan tool. Operate the vehicle within the Conditions for Running DTC. Repeat the procedure until the scan tool indicates the diagnostic test has run. Repeat this procedure for any additional required DTCs that have not run. With a scan tool, observe the I/M System Status display. Did the HO2S Heater System Status update to YES? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
  5. Using scan tool, observe emission related DTC portion of I/M system status display. If scan tool indicates any emission related DTCs, perform appropriate diagnostic test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If scan tool does not indicate any emission related DTCs, system is okay.
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