Cruise Control: Description and Operation

Cruise Control Description and Operation (non 2.0L)

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 cruise control switch
* The clutch pedal position (CPP) switch (if equipped)
* The engine control module (ECM)
* The stop lamp switch
* The cruise release switch
* The throttle actuator control (TAC) motor
* The vehicle speed sensor (VSS)

Cruise Control Engaged

The Cruise Control System will engage and adjust vehicle speeds, based on the activation of the following cruise control switches:

* The On/Off switch
* The + RES switch
* The - SET switch

The engine control module (ECM) monitors the cruise control set/coast and resume/accel 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 in Computers and Control Systems - 2.2L (L61).

Ignition voltage is supplied to the cruise control switch from the 2-ampere electric power steering (EPS) fuse via the ignition 1 voltage circuit. The cruise control switches are arranged in a resistive ladder, 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 that the On/Off switch is active. Similarly, when the set/coast switch or the resume/accel switch are activated, the ECM detects the pre determined voltage signal on the cruise control set/coast and resume/accel switch signal circuit. To engage the Cruise Control System, turn the Cruise Control System ON by pressing the cruise On/Off switch ON and momentarily press the set/coast switch. The ECM will confirm that the cruise control criteria has been met and will record the vehicle speed. The set/coast switch and the resume/accel switch will remain inactive when the ECM has not received the predetermined voltage signal from the On/Off switch. Pressing the accelerator pedal, while the Cruise Control System is engaged, will allow the driver to override the Cruise Control System in order to accelerate the vehicle beyond the current set vehicle speed. When the accelerator pedal is released, the vehicle will decelerate and resume the current set vehicle speed. The driver can also override the current set vehicle speed via the set/coast switch and the resume/accel switch. When the Cruise Control System is engaged, pressing and holding the set/coast switch will allow the vehicle to decelerate from the current set vehicle speed without deactivating the Cruise Control System. When the set/coast switch is released, the ECM will record the vehicle speed and maintain the vehicle speed as the new set vehicle speed. When the Cruise Control System is engaged, momentarily pressing the set/coast switch will allow the vehicle to decelerate at 1.6 km/h (1 mph) increments for each time that the set/coast switch is momentarily pressed, with a minimum vehicle speed of 37 km/h (23 mph). Activating and holding the resume/accel switch, when the Cruise Control System is engaged, will allow the vehicle to accelerate to a greater vehicle speed than the current set vehicle speed. When the resume/accel switch is released, the ECM will record the vehicle speed and maintain the vehicle speed as the new set vehicle speed. When the Cruise Control System is engaged, momentarily activating the resume/accel switch will allow the vehicle to accelerate at 1.6 km/h (1 mph) increments for each time that the resume/accel switch is momentarily activated, with the maximum acceleration total of 16 km/h (10 mph) over the current set vehicle speed. Momentarily activating the resume/accel switch, after the Cruise Control System has been disengaged by pressing the brake pedal, will recall the previous set vehicle speed that is recorded in the ECM.

Cruise Control Disengaged

The engine control module (ECM) disengages the cruise control operation based on the signals from the following switches:

* The stop lamp switch
* The clutch pedal position (CPP) switch
* The cruise release switch
* The cruise control On/Off switch

The cruise release switch and the stop lamp switch are mounted on the brake pedal bracket. When the brake pedal is applied, the normally closed cruise release switch opens and the normally open stop lamp switch closes. The ECM detects a low signal voltage on the cruise release switch signal circuit and a high signal voltage on the stop lamp switch signal circuit. When the clutch pedal is pressed, the normally open CPP switch closes and the ECM detects a high voltage signal on the CPP switch signal circuit. The vehicle speed stored in the memory of the ECM will be erased when the cruise control On/Off button is pressed, or the ignition switch is turned OFF.

The Cruise Control System will disengage when the ECM detects that a driver override function has been active for greater than 60 seconds.

Cruise Control Inhibited

The engine control module (ECM) inhibits the cruise control operation when any of the following conditions exist:

* A cruise control related DTC has been set.
* The vehicle speed is less than 40.2 km/h (25 mph).
* The vehicle is in PARK, REVERSE, NEUTRAL, or 1st gear.
* The engine RPM is too low.
* The engine RPM is too high, with fuel cut OFF.
* The vehicle speed is too high, with fuel cut OFF.
* The system voltage is not between 9-16 volts.
* The Antilock Brake System (ABS)/Traction Control System (TCS) is active for more than 2 seconds.