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 DTCs comprising the monitor have Run and Passed, or any one of the DTCs comprising the monitor have illuminated the MIL. Once all tests are completed, the I/M System Status display will indicate YES in the COMPLETED column. For example, when HO2S Heater Test indicates YES, all oxygen sensor heaters have been diagnosed. If vehicle has 4 heated oxygen sensors, all 4 heater circuits have been diagnosed. I/M SYSTEM STATUS will indicate NO under the COMPLETED column when any 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:

• Vehicle is new from the factory and has not yet been driven through the necessary drive conditions to complete the tests.
• Battery has been disconnected or discharged below operating voltage.
• Control module power or ground has been interrupted.
• Control module has been reprogrammed.
• Control module DTCs have been cleared as part of a service procedure.