Description of on-Board Diagnostics

In the process of controlling the A/C system, the ECC Head 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 two digit numerical trouble code is stored in computer memory when a problem is detected by this self diagnostic system. The trouble Codes can later be displayed by the service technician as and aid in system repair.

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