Monitor Conditions

The downstream oxygen sensors are monitored for faults during the one-shot test and the catalyst monitor test. The one-shot test is activated after the upstream sensor has been used for closed-loop control for 98 seconds, with battery voltage between 11.0 and 16.0 volts. If the downstream sensor switches once while the test is active the test will be terminated. If it does not switch, the one-shot test will be continued to allow the diagnostic tests on the downstream sensor to execute until either a DTC is reported or the one-shot test times out after 160 seconds. The catalyst monitor test is activated after engine run time of 462.5 seconds, with battery voltage between 11.0 and 16.0 volts, vehicle speed between 55 and 150 km/h (34 and 93 mph) with variation of less than 8 km/h (5 mph), engine temperature above 70° C (158°_F) and EVAP purge active. The test runs for a maximum of 60 seconds.