Chevrolet Trax: Inspection/maintenance system check

Diagnostic Instructions

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

Circuit/System Description

Several states require for a vehicle to pass on-board diagnostic (OBD) system tests and inspection/maintenance (I/M) emission inspections in order to renew license plates. This is accomplished by viewing the Inspection/Maintenance System Status or Data display on a scan tool. Using a scan tool, the technician can observe the I/M status in order to verify that the vehicle meets the criteria that complies with the local area requirements.

Condition for Updating the Inspection/Maintenance Emission System Status

Each system monitor requires at least one, and sometimes several, diagnostic tests. The result of each test is reported by a diagnostic trouble code (DTC). A system monitor is complete when either all of the DTCs composing the monitor have Run and Passed, or when any one of the DTCs comprising the monitor has illuminated the malfunction indicator lamp (MIL). Once the system monitor is complete, the Inspection/Maintenance System Status or Data will indicate YES in the completed or Value column.

For example, when the HO2S heater status indicates YES, either all of the oxygen sensor heater tests have passed or one of the tests has illuminated the MIL. If the vehicle has two heated oxygen sensors, either both heater circuit tests have passed or one of the heater circuit tests has illuminated the MIL. The Inspection/Maintenance System Status or Data will indicate NO under the Completed or Value column when any of the required tests for that system have not run. The following is a list of conditions that may set the Inspection/Maintenance System Status or Data indicator to NO:

• The vehicle is new from the factory and has not yet been driven through the necessary drive conditions to complete the tests.
• The battery has been disconnected or discharged below operating voltage.
• The engine control module (ECM) power or ground has been interrupted.
• The ECM has been reprogrammed.
• The ECM DTCs have been cleared.

Monitored Emission Control Systems

The OBD II System monitors all emission control systems that are on-board. The OBD II regulations require monitoring of the following:

• The air conditioning system
• The catalyst efficiency
• Comprehensive component monitoring, emission related inputs and outputs
• The evaporative emission (EVAP) system
• The fuel delivery system
• Heated catalyst monitoring
• Misfire monitoring
• The oxygen sensor system (HO2S)
• The oxygen sensor heater system (HO2S heater)

For the specific DTCs required for each system, refer to Inspection/Maintenance (I/M) System DTC Table.

Systems such as fuel delivery, misfire, and comprehensive components may not be listed in a system status list.

These tests run continuously and do not require an inspection/maintenance system status indicator.

Circuit/System Verification

1. Verify that all Inspection/Maintenance System Status or Data indicators report YES, and that no I/M Test DTCs are present.

• If any I/M Test DTCs are set

Refer to Diagnostic Trouble Code (DTC) List - Vehicle .

• If no I/M Test DTCs are set

2. All OK.

Circuit/System Testing

NOTE: Many DTC related repairs will instruct the technician to clear the DTC information. Clearing the DTC will reset the Inspection/Maintenance System Status or Data indicators to NO. Performing the I/M Complete System Set Procedure will set each of the I/M System Status indicators to YES.

1. Verify no I/M DTCs are present.

• If an I/M DTC is set that would prevent the I/M System Status tests from completing, diagnose that DTC before continuing.

Refer to Inspection/Maintenance (I/M) System DTC Table.

• If no I/M DTCs are set

2. Review applicable service bulletins for software updates that would prevent the I/M System Status tests from completing.

• If a control module re-program or other repair is required,

Perform the Inspection/Maintenance Complete System Set Procedure after repair.

• If no repair is required

3. Observe the Inspection/Maintenance System Status or Data indicators.

• If any Inspection/Maintenance System Status or Data indicators report NO

Perform the Inspection/Maintenance Complete System Set Procedure.

• If no Inspection/Maintenance System Status or Data indicators report NO

4. All OK.

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