Cruise control is a speed control system that maintains a desired vehicle speed
under normal driving conditions at vehicle 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 clutch start switch, if equipped with a manual transmission |
• | The engine control module (ECM) |
• | The resume/accel switch |
• | The torque converter clutch (TCC) brake/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 the vehicle speed based on
the activation of the following cruise control switches:
The engine control module (ECM) monitors the signal circuits of the cruise control
switches in order to determine when to capture and maintain the selected vehicle speed.
The ECM uses the throttle actuator control (TAC) motor in order to control the vehicle
speed. For further information on the TAC system, refer to
Throttle Actuator Control (TAC) System Description
in Engine Controls - 6.0L.
The cruise control switches are located on the multifunction/turn signal lever.
Ignition positive voltage is supplied from the 10-ampere CRUISE fuse to the
cruise control switch via the ignition 3 voltage circuit. When the normally
open cruise control on/off switch is turned ON, the switch closes and the ECM detects
a high signal voltage on the cruise control on switch signal circuit. When the normally
open set/coast switch is pressed, the switch closes and the ECM detects a high signal
voltage on the cruise control set/coast switch signal circuit. To engage the cruise
control system, turn the on/off switch ON and momentarily press the set/coast switch.
The ECM will confirm that the cruise control enable criteria has been achieved. The
ECM will engage the Cruise Control System and record the selected vehicle speed. The
ECM sends a class 2 message to the instrument panel cluster (IPC) in
order to illuminate the Cruise indicator. 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 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 is momentarily pressed,
with a minimum vehicle speed of 37 km/h (23 mph). When the normally
open resume/accel switch is activated, the switch closes and the ECM detects a high
signal voltage on the cruise control resume/accel switch signal circuit. 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 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 clutch start switch |
• | The torque converter clutch (TCC) brake/cruise release switch |
The TCC brake/cruise release switch and the stop lamp switch are incorporated
into an assembly and are mounted to the brake pedal bracket. Pressing the brake pedal
while the cruise control is engaged will disengaged the Cruise Control System. The
ECM monitors the TCC brake switch/cruise control release signal circuit and the stoplamp
switch signal circuit. When the brake pedal is pressed, the normally closed TCC brake
switch opens and the normally open stoplamp switch closes. The ECM detects a low signal
voltage on the TCC brake switch/cruise control release signal circuit and detects
a high signal voltage on the stop lamp switch signal circuit. When the clutch pedal
is applied, the normally closed clutch switch opens and the ECM detects a low voltage
signal on the clutch start switch signal circuit. The Cruise Control System will disengage
when the cruise control on/off switch is turned OFF. When the Cruise Control System
is disengaged, the ECM sends a class 2 message to the instrument panel cluster
(IPC) in order to deactivate the Cruise indicator. The vehicle speed stored in the
memory of the ECM will be erased when the cruise control on/off switch is turned to
OFF, or the ignition switch is turned OFF.
The Cruise Control System will disengage when the ECM detects that the accelerator
pedal override is 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 System related DTC has been set. |
• | The vehicle speed is less than 40 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. |
• | The vehicle speed is too high. |
• | The system voltage is not between 9-16 volts. |
• | The antilock brake system/traction control system is active for more than
2 seconds. |