On-Board Diagnostics (OBD) refers to the vehicles self diagnostic system. The system was developed to help motorist and service technicians diagnose and service vehicles computerized engine management systems, as well as to inform the motorist when a potential problem exists regarding the emissions control systems of the vehicle. Αt the beginning with the 1996 model year, a new system was develope. The new system known as OBDII requires all light duty cars and trucks to monitor specific systems using generic criteria for evaluation and reporting of system status, and for indicating problems to the motorist and/or technician.