Are lights the only thing the OBD uses to warn the driver of issues?
Malfunction Indicator Lamps (MIL) and audible alarms are currently the only means by which the On-Board Diagnostics (OBD) system can inform the driver of any issues that adversely affect the operation of the engine or other electronically controlled system.
The MIL, or Check Engine Light, being illuminated doesn’t automatically mean that your car is about to break down. It does mean that the Powertrain Control Module (PCM) has detected a failure that is causing your tailpipe emissions to exceed acceptable limits. Basically, the MIL is telling you that you are polluting the air. You need to have a trained technician check the OBD system to determine what issues the PCM has detected and to have them addressed. Not only will your engine run efficiently, but you won’t be polluting the atmosphere, either.