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 provides 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 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 10-15 volts.
    • The barometric pressure (BARO) is more than 75 kPa.
    • The engine coolant temperature (ECT) at start-up is less than 42°C (108°F).
    • The intake air temperature (IAT) is between 2-32°C (36-90°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).
    • The fuel level is between 25-75 percent.

Circuit/System Verification

Review the I/M System Status indicators. All I/M System Status indicators should report YES.

Inspection/Maintenance (I/M) System 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. Start and idle the engine for 2 minutes.
  6. Warning: Refer to Road Test Warning in the Preface section.

  7. Close the hood, release the parking brake and Accelerate at part throttle to 72-80 km/h (45-50 mph) with this speed maintained until the engine reaches operating temperature, 8-10 minutes.
  8. Continue operation under these conditions for an additional 6 minutes.
  9. Accelerate at part throttle to 90 km/h (55 mph) with this speed maintained for 2 minutes.
  10. Release the accelerator pedal for at least 10 seconds. This will allow the vehicle to enter the decel fuel cut-off.
  11. Note: 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.

  12. 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.
  13. 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.
  14. Observe the I/M System Status with a scan tool. All of the I/M System Status indicators should display YES.
  15. 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 6-11 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.