E Code Descriptions

Fig. 1 ECM diagnostic codes:

During diagnosis of the electronic climate control system, refer only to the specific codes corresponding to the system. Do not enter or erase any codes associated with the electronic climate control system or any other engine control system unless directed to do so within the diagnostic charts.

In the process of controlling the various subsystems, the ECM and BCM monitor operating conditions for possible system malfunctions (a hard fault or ``fail-soft'' conditions).

By comparing system operating conditions against standard (predetermined) operating limits, certain circuit and component malfunctions can be detected.

A three-digit numerical ``trouble code'' is stored within the computer memory when a problem is detected. These trouble codes can be displayed during system diagnosis and repair. Computer controlled diagnostic messages and/or telltales will appear in the event of a hard fault or fail-soft condition.

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