It shouldnt have continuity to ground, it goes to the bulb in dash, not a ground buss. If you want to test it, get a test light, hook the clamp to the CEL pin and the other end to batt +. It should turn on the light when key is on. It will not flash codes unless you put it into code reading mode. You can either flash code via light w ten code flash or you can scan it with OBD I code reader which is more accurate .