Hrm. I've done this myself with the OBD-II reader and some do come up pretty quickly, but they took all some amount of running/driving to be ready if you reset

Hrm. I've done this myself with the OBD-II reader and some do come up pretty quickly, but they took all some amount of running/driving to be ready if you reset the ECU...which people would try if there's a code stored / check engine light on. Some of them take quite a while to be ready.