With the SDS shop tester in activations screen, i could turn on airinjection, and o2 is required to be less than 40 mv ,with my bad o2 sensor i only dropped to 60-80mv, unplugging a vac line such as purge line,02 sensor should immediatly drop to under 40 mv, replaced my o2 sensor and now mv drops to 17mv when activating airinjection, o2 sensor solved problem.