Chevrolet Sonic Repair Manual: 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 the inspection/maintenance emission inspection in order to renew license plates. This is accomplished by viewing the inspection/maintenance system status display on a scan tool. Using a scan tool, the technician can observe the inspection/maintenance system status in order to verify that the vehicle meets the criteria that comply 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 display will indicate YES in the completed 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 will indicate NO under the completed 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 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

Review the inspection/maintenance system DTC Table System Status indicators. All inspection/maintenance system DTC Table system status indicators should report YES.

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 DTC Table system status indicators to NO. Performing the inspection/maintenance complete system set procedure will set each of the inspection/maintenance system status indicators to YES.

1. Observe the Engine DTC information with a scan tool.

• If a DTC is set that may prevent the inspection/maintenance system status tests from completing, diagnose that DTC before continuing. Refer to Inspection/Maintenance (I/M) System DTC Table.

Review applicable service bulletins for software updates that may prevent the inspection/maintenance system status tests from completing.

• If a control module reprogram or other repair is required, perform the . Inspection/Maintenance Complete System Set Procedure

Observe the inspection/maintenance system status indicators.

• If any inspection/maintenance system status indicators report NO, perform the Inspection/Maintenance Complete System Set Procedure.

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