Preliminary Test Description

The operation of the cruise control system is integral with the body control module (BCM) or power control module (PCM). The BCM or PCM monitors the cruise control system and other systems by comparing the actual operating conditions to standard values stored in memory. When certain system malfunctions are detected, a three digit diagnostic trouble code is stored in the BCM memory. These diagnostic trouble codes can be displayed to aid in system diagnosis. In this manner, the speed control system can be diagnosed by accessing fault codes, if they exist, that pertain to the speed control system.

Codes other than those described below may be stored in the BCM memory and displayed when the system is accessed to diagnose cruise control malfunctions. It may be necessary to diagnose these codes and identify the non-speed control related failure in order to ensure proper speed control system operation.