GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provide an overview of each diagnostic category.

Description

The purpose of the Inspection/Maintenance (I/M) complete system set procedure is to satisfy the enable criteria necessary to execute all of the I/M readiness diagnostics and complete the trips for those particular diagnostics. When all I/M monitored diagnostic tests are completed, the I/M System Status indicators are set to YES. Perform the Inspection/Maintenance (I/M) Complete System Set Procedure if any I/M System Status indicators are set to NO.

Conditions for Meeting a Cold Start

    • The ignition voltage between 10 and 16 volts.
    • The barometric pressure (BARO) is greater than 72 kPa.
    • The start-up engine coolant temperature (ECT) is greater than -5°C (23°F).
    • The start-up intake air temperature (IAT) is less than 40°C (104°F).
    • The difference between the start-up IAT and ECT are within 3°C (5°F).
    • The engine is OFF for greater than 6 hours or the following conditions must be met:
      • The start-up IAT minus start-up ECT are within 12°C (22°F).
      • The start-up ECT minus start-up IAT are within 50°C (90°F).
    • Fuel level is between 25 and 75 percent

Circuit/System Verification

Review the Inspection/Maintenance (I/M) System Status indicators. All I/M System Status indicators should report YES.

Inspection/Maintenance (I/M) System Set Procedure

    Important: Whenever the ignition is turned ON, ignition positive voltage is supplied to the heated oxygen sensor (HO2S) heaters. After verifying the enable criteria, turn OFF the ignition for approximately 5 minutes to allow the sensors to cool before continuing with the test. Once the engine is started, do NOT turn the engine OFF for the remaining portion of the set procedure.

  1. Ensure that the vehicle meets the conditions for a cold start listed above.
  2. If the EVAP I/M System Status indicator displays NO, perform the EVAP Service bay test if applicable.
  3. Turn OFF all accessories; HVAC system, other electrical loads, including aftermarket/add-on equipment, etc., and open the hood.
  4. Set the vehicle parking brake and ensure the vehicle is in park for automatic transmission or neutral for manual transmission.
  5. Turn the ignition ON for 1 minute.
  6. Start and idle the engine for 5 minutes.
  7. Run the engine for 6 minutes within the following conditions:
  8. • Calculated air flow is between 9-30 g/s
    • Engine speed steady between 1300-3000 RPM
  9. Apply and hold brake pedal, and shift to Drive for automatic, or apply clutch pedal for manual and operate the vehicle within the following conditions for 2 minutes:
  10. • MAP signal is greater than 12 g/s
    • Engine speed is greater than 1000 RPM

    Important: Do NOT touch the accelerator pedal until told to do so. A change in TP Sensor angle or an increase in engine speed may invalidate this portion of the test.

  11. Release the accelerator pedal and shift the vehicle to Park for automatic, or Neutral and release clutch pedal for manual, and allow the engine to idle for 2 minutes.
  12. Caution: Refer to Road Test Caution in the Preface section.

  13. Close the hood, release the parking brake and drive vehicle at 90 km/h (55 mph) for 2 minutes.
  14. Release the accelerator pedal for at least 10 seconds. This will allow the vehicle to enter the decel fuel cut off.
  15. Safely stop the vehicle, with the engine in drive for automatic or neutral with the clutch pedal depressed and parking brake applied for manual. Allow the vehicle to idle for 2 minutes.
  16. Important: Do NOT disturb the vehicle or turn ON the ignition until told to do so. Disturbing the vehicle may invalidate this portion of the test.

  17. Shift the vehicle to park for automatic and neutral for manual. Turn OFF the ignition and exit the vehicle. Do NOT disturb the vehicle for 45 minutes.
  18. Observe the Inspection/Maintenance (I/M) System Status with a scan tool. All of the I/M System Status indicators should display YES.
  19. If the EVAP I/M System Status indicator displays NO, turn OFF the ignition, ensure that the vehicle meets the conditions for a cold start, and repeat steps 13-18 three more times, or until the EVAP I/M System Status indicator transitions to YES. If the indicator continues to display NO, refer to the Inspection/Maintenance (I/M) System DTC Table to identify the DTCs that did not run.
    If any of the I/M System Status indicators display NO, refer to the Inspection/Maintenance (I/M) System DTC Table for the indicator which did not display YES. The I/M System DTC Table identifies the DTCs associated with each I/M System Status Indicator.