INSPECTION/MAINTENANCE (I/M) COMPLETE SYSTEM SET PROCEDURE
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Description
Several states require that a vehicle pass On-Board Diagnostic (OBD) system tests and the I/M emission inspection in order to renew license plates. This is accomplished by viewing the I/M system status display on a scan tool. Using a scan tool, the technician can observe the I/M system status in order to verify that the vehicle meets the criteria that complies with the local area requirements.
The System Status display indicates only if the PCM has completed the required tests (DTCs). The System Status display does not necessarily mean that the test has passed. If a failure indication is present for a DTC associated with one of the systems, that test has failed. Diagnosis and repair are necessary in order to meet the I/M requirement. Verify that the vehicle passes all of the diagnostic tests associated with the displayed System Status prior to returning the vehicle to the customer.
Conditions for Updating I/M System Status
Each system requires at least one, and sometimes several, diagnostic tests. The results of these tests are reported by a Diagnostic Trouble Code (DTC). A system monitor is complete when either all of the DTCs comprising the monitor have run and passed, or any one of the DTCs comprising the monitor have illuminated the MIL. Once all of the tests are completed, the I/M System Status display will indicate YES in the COMPLETED column. For example, when the HO2S Heater Test indicates YES, all of the oxygen sensor heaters have been diagnosed. If the vehicle has four heated oxygen sensors, all four heater circuits have been diagnosed. The I/M 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 would set the I/M 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 control module power or ground has been interrupted.
- The control module has been reprogrammed.
- The control module DTCs have been cleared as part of a service procedure.
Monitored Emission Control Systems
The OBD-II System monitors all emission control systems that are on-board. Not all vehicles have a full complement of emission control systems. For example, a vehicle may not be equipped with secondary Air Injection (AIR) or Exhaust Gas Recirculation (EGR). The OBD-II regulations require monitoring of the following
- Air conditioning system.
- Catalytic converter efficiency.
- Comprehensive component monitoring. Emission related inputs and outputs.
- Evaporative (EVAP) emissions system.
- Exhaust Gas Recirculation (EGR) system.
- Fuel delivery system.
- Heated catalyst monitoring.
- Misfire monitoring.
- Oxygen Sensor system (O2S or HO2S).
- Oxygen sensor heater system (HO2S heater).
- Secondary Air Injection (AIR) system.
Systems such as fuel delivery, misfire, and comprehensive components may not be listed in a system status list. These tests run continuously on some vehicles and may not require an indicator.
