Cruise Control Description and Operation: Notes

WARNING: This page is about a different car, the 2008 Isuzu i-370, 2008 Isuzu i-290, 2008 GMC Canyon, and 2008 Chevrolet Colorado. However, it is still accessible from the selected car via links, so may be relevant.

Cruise control is a speed control system that maintains a desired vehicle speed under normal driving conditions at speeds above 40 km/h (25 mph). Steep grades may cause variations in the selected vehicle speeds.

The following are the main components of the cruise control system:

The accelerator pedal
The cruise control switch
The engine control module (ECM)
The clutch pedal position (CPP) sensor, if equipped with a manual transmission
The stop lamp switch
The torque converter clutch (TCC) brake/cruise release switch
The throttle actuator control (TAC) motor
The vehicle speed sensor (VSS)

The engine control module (ECM) monitors the cruise control switch signal circuit in order to determine when to capture and maintain the vehicle speed. The ECM monitors the vehicle speed sensor signal circuit in order to determine the vehicle speed. The ECM uses the throttle actuator control (TAC) motor in order control the vehicle speed. For further information on the TAC system, refer to Throttle Actuator Control (TAC) System Description for the 2.9L engine or Throttle Actuator Control (TAC) System Description for the 3.9L engine. Ignition voltage is supplied to the cruise control switch from the 10 ampere CRUISE fuse via the ignition 1 voltage circuit. The cruise control function switches are arranged in a resistive ladder design, with each cruise control function switch having a different resistance value. The ECM detects a specific voltage value that is associated with the cruise control function switch being activated. When the normally open cruise control ON/OFF switch is turned ON, the switch closes and the ECM detects a predetermined voltage signal on the cruise control switch signal circuit indicating the switch is ON. Similarly, when the normally open RESUME/ACCEL switch or the normally open SET/COAST switch are pressed, the switch closes and the ECM detects the predetermined voltage signal on the cruise control resume/accel and set/coast switch signal circuit. The RESUME/ACCEL switch or the SET/COAST switch will remain inactive when the ECM has not received the predetermined voltage signal from the on/off switch.