GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2004 🢒 Colorado Pickup - 2WD 🢒 Engine 🢒 Engine Controls - 2.8L (LK5) 🢒 Inspection/Maintenance (I/M) Catalyst System Set Procedure

Description

The purpose of this procedure is to satisfy the enable criteria necessary to execute an inspection/maintenance (I/M) system monitor for the catalyst system. The system monitor is comprised of the test results from one or more DTCs. This procedure may be used to set the Catalyst I/M System Status display on the scan tool to YES. The Catalyst I/M System Status display indicates whether or not the control module has completed the system monitor. The system monitor completes when either all DTCs comprising the monitor run and pass, or any DTC comprising the monitor illuminates the malfunction indicator lamp (MIL). If one of the DTCs comprising the monitor is set and the MIL is not illuminated, the necessary trips are required to illuminate the MIL before the monitor will complete. Once the monitor completes, The Catalyst I/M System Status display will be updated to YES.

Conditions for Running
    • The engine has been running longer than 10 minutes.
    • The barometric pressure (BARO) is more than 72 kPa.
    • Engine coolant is at operating temperature, 69-125°C (157-257°F).
    • The intake air temperature (IAT) is between -20 and +80°C (-4 and +176°F).
    • The engine is in closed loop fuel control.
    • The battery voltage is more than 9 volts.

Diagnostic Aids

The control module runs a maximum of 12 tests per trip. If there is an impending failure, the system may require more time than was allotted in the system set procedure. If any DTCs do not run and no DTC is set, review the appropriate scan tool data list and service information. This will give an indication of why the DTCs do not run. Some may abort due to changes in the conditions while running. For example, changes in engine load such as a cooling fan or A/C compressor clutch turning ON, may cause a DTC to abort. If the Catalyst I/M System Status does not update to YES, the procedure can be repeated until a YES status is achieved.

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, e.g., A/C, blower fan, etc.
  3. Start and allow the engine to idle for 2 minutes.

    4. 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:

  4. Acceleration at part throttle to 89 km/h (55 mph) with this speed maintained until the engine reaches operating temperature. This may take up to 10 minutes.
  5. Continue operating under these conditions for an additional 8 minutes after the engine reaches operating temperature.
  6. Deceleration to 0 km/h (0 mph).
  7. Engine idling for 1 minute while the following criteria is maintained:
    8. • Service brake depressed
    • Automatic transmission in DRIVE or manual transmission in NEUTRAL with the clutch pedal depressed
  8. Observe the I/M System Status display with a scan tool.

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 Diagnostic Trouble Code (DTC) List

Go to Step 4

4

  1. Refer to Inspection/Maintenance (I/M) System DTC Table to determine which DTCs are required to run in order to update the Catalyst I/M System Status to YES.
  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 numbers 4 and 5 of this step for any additional required DTCs that have not run.
  7. Observe the I/M System Status display with a scan tool.

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?

Go to Diagnostic Trouble Code (DTC) List

System OK