Cruise Control System Diagnosis

Depending on the cruise control complaint, the ECM DTCs that would affect cruise operation mentioned in "Cruise Control System Operation" should be diagnosed and corrected first. If no DTCs exist, but a cruise control system problem does, the "Cruise Control System Check" chart should be the starting point. This will either locate the problem or will refer to a chart which will aid in diagnosis.

The Scan tool can be used to help diagnose an inoperative cruise control system or other faults related to the system. The Scan tool displays CRUISE SWITCH, CRUISE SET/COAST and CRUISE RESUME/ACCEL inputs for the cruise control switch states. The Scan tool also displays BRAKE SWITCH (stop lamp switch) and CRUISE BRAKE SWITCH states. Cycling these switches while monitoring each parameter may lead to the cause of an intermittent cruise control condition.