Cruise control is a vehicle speed control system which maintains a desired vehicle speed without the driver having to continually apply foot pressure to the accelerator pedal.
The cruise control system is an Electro-motor system, i.e. it uses a stepper motor to control vehicle speed. A throttle relaxer servo is fitted as part of the traction control system to provide engine torque control. The throttle relaxer momentarily reduces
the throttle opening angle when traction loss occurs. There is no electronic interface between the throttle relaxer and the cruise control module.
The cruise control module also uses an output from the powertrain control module (PCM) for vehicle speed, and provides an input to the instrument cluster for cruise control status indication.
When the cruise control module is powered up via the cruise control ON/OFF push-button switch, the cruise control module activates an input to the instrument cluster. The instrument cluster sees this line as active and sends a message to the Multifunction
Display (MFD) to turn its CRUISE icon on.
When the CRUISE switch is rotated to the SET/DECEL position (provided the vehicle speed is above 25 mph and either the brake or clutch pedal is not pressed) the cruise control module activates an input to the instrument cluster. The instrument cluster
sees this line as active and sends a message to the MFD to turn its ACTIVE icon on and in turn, the instrument cluster informs the PCM via the serial data interface to use a specific transmission shift pattern. The transmission shift pattern is designed primarily
for cruise mode, having fewer transmission down shifts and reduced transmission gear change activity.