Cruise Control Description and Operation w/ ETC
Cruise control is a speed control system that maintains
a desired vehicle speed under normal driving conditions. However, steep
grades may cause variations in the selected speeds. The electronic
cruise control system has the capability to CRUISE, COAST, RESUME
SPEED, ACCELERATE, and TAP-UP or TAP-DOWN.
The main parts of the cruise control system are:
• | The throttle actuator control module (TAC) |
• | The function control switches |
• | The stop lamp switch assembly |
• | The powertrain control module (PCM) |
The cruise control system uses the TAC module to maintain the desired
vehicle cruise speed and operation. The TAC and the powertrain control module
(PCM) communicate together to vary the throttle opening in each different
cruise control mode. The PCM monitors vehicle speed and operates
the throttle actuator. The throttle actuator operates in response
to the TAC module, to maintain the desired cruise speed. The throttle
actuator motor moves the throttle blade. The PCM assembly contains
a low speed limit which will prevent system engagement below a
minimum speed of 40 km/h (25 mph). The TAC or PCM module assembly
are not serviceable.
The operation of the cruise control is through the function control
switches located on the multifunction turn signal lever. The cruise control
function control switches includes the ON/OFF, SET/COAST, R/A .
The switch assembly provides driver control of the cruise control system.
The multiple function stop lamp switch is used to disengage the cruise
control. A cruise control release switch circuit and a stop lamp switch
circuit are used. The stop lamp switch is mounted to the brake pedal
bracket . To disengage the system the driver presses the brake
pedal . The speed of the vehicle at brake actuation will be stored
in the memory of the TAC module.
With cruise control, the vehicle can maintain a speed of about 40 km/h
(25 mph) or more without keeping your foot on the accelerator. When the
driver turns off the cruise control ON/OFF switch or ignition switch,
the cruise control turns off. The vehicle speed stored in the memory
of the TAC module will be lost.
Ignition positive voltage is supplied from the ETC fuse,
to the TAC module. The TAC module is grounded to G103. When the cruise
control ON/OFF switch is on, ignition positive voltage is applied
to the cruise on switch signal terminal of the TAC module. If the driver
has not pressed the brake pedal , ignition positive voltage is
supplied through the switches, to the cruise control brake pedal switch
signal terminals of the PCM. Cruise control is canceled when the
driver presses the brake pedal . The stop lamp switch closes,
applying battery positive voltage to the stop lamp signal circuit of
the TAC module. Voltage is also removed from the brake pedal signal
circuit at the PCM. When pressing the SET/COAST button on the multifunction
turn signal lever, ignition positive voltage is applied to the set/coast
switch signal terminal of the TAC module. When pressing the R/A
on the control switch, ignition positive voltage is applied to the
resume/accelerate switch signal terminal of the TAC module.
When the cruise switch is in the ON position, and the driver presses
the SET/COAST button, the TAC module notifies the PCM that the cruise control
is requested. The PCM then checks to see that the cruise control
enable criteria is met. If the cruise control criteria has been met
the PCM sends a class 2 message to the instrument panel cluster (IPC)
to illuminate the cruise light, if equipped
The PCM will inhibit cruise control:
• | When vehicle speed is less than 40 km/h (25 mph). |
• | When in PARK, REVERSE, NEUTRAL, or 1st gear. |
• | With high engine RPM, e.g. fuel cut-off |
• | When vehicle speed is to high |
• | When an over or under charged battery voltage condition exists |
• | Antilock brake system/traction control system is active for more
than 2 seconds |
If the PCM determines that any of the cruise control inhibit conditions
are present, the PCM will disengage the cruise control. The PCM accomplishes
this through data communication with the TAC module. If the PCM disables
the cruise control for an inhibiting event it will record the reason
for disengagement in the Disengage Definition data file.
Cruise Control Description and Operation w/o ETC
Cruise control is a speed control system that maintains
a desired vehicle speed under normal driving conditions. However, steep
grades may cause variations in the selected speeds. The electronic cruise
control system has the capability to CRUISE, COAST, RESUME SPEED, ACCELERATE,
and TAP-UP or TAP-DOWN.
The main parts of the cruise control system are:
• | The cruise control module assembly |
• | The function control switches |
• | The cruise control release switch |
• | The stop lamp switch assembly |
• | The vehicle speed sensor |
The cruise control system uses the cruise control module assembly to
maintain the desired vehicle cruise speed and operation. The cruise control
module assembly has an electronic controller and an electric stepper
motor to vary the throttle in each different cruise control mode.
The electric controller monitors vehicle speed and operates the electric
stepper motor. The stepper motor operates in response to the electronic
controller, to maintain the desired cruise speed. The electric stepper
motor moves a strap that is attached to the cruise control cable which
moves the throttle linkage. The cruise control module assembly contains
a low speed limit which will prevent system engagement below a minimum
speed of 40 km/h (25 mph). The module assembly is not serviceable.
The operation of the electronic controller is controlled by the function
control switches located on the multifunction turn signal lever. The cruise
control functional control switches include the ON/OFF, SET/COAST and
R/A switch. The switch assembly provides driver control of the
cruise control system.
The stop lamp switch controls both the cruise control release signal
and stoplamp signal. These signal circuits are used to disengage the cruise
control. The stop lamp switch assembly is mounted on the brake pedal
bracket. To disengage the system electrically the driver presses the
brake pedal. The speed of the vehicle at brake actuation will be stored
in the memory of the cruise module.
With cruise control, you can maintain a speed of about 40 km/h (25 mph)
or more without keeping your foot on the accelerator. When the driver turns
off the on/off switch, or the ignition switch, the cruise control turns
off. The vehicle speed stored in the memory of the cruise module will
be lost.
Ignition positive voltage is supplied from the cruise fuse,
to the cruise control module and cruise control switch. The cruise control
module is grounded to the chassis. When the cruise control ON/OFF switch
is on, ignition positive voltage is applied to the cruise on switch
signal circuit of the cruise control module. If the driver has not
pressed the brake pedal, ignition positive voltage is supplied through
the cruise control release circuit, to the cruise control release signal
terminal of the cruise control module. . When the driver presses
the brake pedal, battery positive voltage is supplied from the stop
lamp fuse, through the closed stop lamp switch to the stop lamp switch
signal terminal of the cruise control module. As this operation occurs,
ignition positive voltage is removed from the cruise release signal
circuit. When the SET/COAST is pressed on the control switch, ignition
positive voltage is applied to the set/coast switch signal terminal
of the cruise control module. When pressing the R/A on the control
switch, ignition positive voltage is applied to the resume/ accelerate
switch signal terminal of the cruise control module.
The cruise control module receives a vehicle speed signal input from
the Powertrain Control Module (PCM). In operation, the voltage varies between
0 V and 5 V.
The cruise control module, cruise indicator control terminal, sends
a signal to the PCM when cruise is engaged. The cruise control module, cruise
cancel signal terminal, is a circuit used by the PCM to inhibit cruise
control when conditions inconsistent with cruise operation are present.
After the cruise control engage criteria has been met and the cruise
ON and Set/Coast have been commanded, the cruise control module sends a
signal to the PCM that the cruise control is engaged. The PCM then
send a class 2 message to the instrument panel cluster (IPC) to illuminate
the cruise light.
The PCM will inhibit cruise control:
• | When vehicle speed is less than 40 km/h (25 mph). |
• | When in PARK, REVERSE, NEUTRAL, or 1st gear. |
• | With high engine RPM, e.g. fuel cut-off |
• | When vehicle speed is to high |
• | When an over or under charged battery voltage condition exists |
• | Antilock brake system/traction control system is active for more
than 2 seconds |
If the PCM determines that any of the cruise control inhibit conditions
are present, the PCM will disengage the cruise control. The PCM accomplishes
this by opening the cruise control inhibit/enable signal circuit.