- The vehicle’s OBD system connector has been removed or is otherwise not working properly. The OBD check cannot be completed if the connector is missing or is not working properly.
- The Malfunction Indicator Light does not illuminate at all when the ignition key is turned to the “on” position. When the vehicle’s OBD system detects a problem, it turns on the warning light to alert the driver to a problem. However, if the light cannot illuminate because the bulb has burned out or is otherwise not working, the driver would not be alerted to the problem.
- The Malfunction Indicator Light on the instrument panel is on (and/or commanded on by the vehicle’s on board computer) while the engine is running. This indicates that the OBD system has identified a problem which must be repaired. In this case, one or more diagnostic trouble codes will also be reported by the vehicle’s OBD system and these codes will help your technician diagnose and repair your vehicle.
Agency of Transportation