Trouble Codes

In process of controlling various subsystems, PCM, DERM, EBTCM, RSS Module and BCM continually monitor operating conditions for possible system malfunctions. By comparing system conditions against standard operating limits, certain circuit and component malfunctions can be detected. A three digit numerical Trouble Code is stored in computer memory when a problem is detected by this self-diagnostic system.

These trouble codes can later be displayed as an aid in system repair. The occurrence of certain system malfunctions require that vehicle operator be alerted to problem so as to avoid prolonged operation of vehicle under subnormal system operation. Computer controlled diagnostic messages and/or telltales will appear under these conditions which indicate that service is required.

If a particular malfunction would result in unacceptable system operation, self-diagnostics will attempt to minimize effect by taking "Failsoft" action. Failsoft action refers to any specific attempt by computer system to compensate for the detected problem. A typical "Failsoft" action would be a situation of a fixed input value when a sensor is detected to be open or shorted.