Cruise Control Description and Operation 2.2L
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 brake pedal position (BPP) sensor |
• | The body control module (BCM) |
• | The cruise control on/off switch |
• | The engine control module (ECM) |
| The + RES switch is the equivalent to an accel/resume switch. |
| the - SET switch is the equivalent to a set/coast switch. |
• | The throttle actuator control (TAC) motor |
• | The vehicle speed sensor |
Cruise Control Engaged
The cruise control system will engage and adjust vehicle speeds, based on the
activation of the following cruise control switches:
The BCM monitors the signal circuit of the cruise control switches. The BCM
relays the cruise control switch status to the ECM via the GMLAN serial data circuit.
The ECM uses the status of the cruise control switch to determine when to capture
and maintain the vehicle speed. The ECM monitors the vehicle speed signal circuit
in order to determine and the desired vehicle speed. The ECM uses the TAC motor in
order to maintain the vehicle speed. For further review of the TAC system, refer to
Throttle Actuator Control (TAC) System Description
in
Engine Controls - 2.2L (L61).
Ignition voltage is supplied to the cruise control switch from the 2-ampere
RUN/CRANK ELEC fuse located in the integrated BCM fuse block. The cruise control function
switches are arranged in a resistive ladder design, with each cruise control function
switch having a different resistance value. The BCM detects a specific voltage value
that is associated with any cruise control function switch being activated. When the
normally open cruise control on/off switch is turned ON, the switch closes and the
BCM detects a predetermined voltage signal on the cruise control set/coast and resume/accelerate
switch signal circuit. The BCM sends a GMLAN serial data message to the ECM indicating
that the on/off switch is active. Similarly, when the + RES switch or the - SET switch
are pressed, the normally open switch closes and the BCM detects the predetermined
voltage signal on the cruise control set/coast and resume/accel switch signal circuit.
To engage the cruise control system, ensure that the vehicle speed is above 40.2 km/h
(25 mph), turn the cruise on/off switch ON and momentarily press the - SET switch.
The ECM will engage the cruise control system and record the vehicle speed. The ECM
sends a GMLAN sreial data message to the instrument panel cluster (IPC) in order to
illuminate the Cruise indicator in the IPC. The - SET switch or the resume/accelerate
switch will remain inactive when the BCM 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 switch
and the resume/accelerate switch. When the cruise control system is engaged, pressing
and holding the - SET switch will allow the vehicle to decelerate from the current
set vehicle speed without deactivating the cruise control system. When the - SET 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 switch will allow the vehicle to decelerate at 1.6 km/h
(1 mph) increments for each time that the - SET is momentarily pressed, with
a minimum vehicle speed of 37 km/h (23 mph). Pressing and holding the
+ RES 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
+ RES 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 + RES switch will allow the vehicle to accelerate at 1.6 km/h
(1 mph) increments for each time that the + RES switch is momentarily pressed,
with the maximum acceleration total of 16 km/h (10 mph) over the current
set vehicle speed. Momentarily pressing the + RES 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 ECM disengages the cruise control operation based on the signals from the
following switches:
• | The cruise control on/off switch |
The BPP sensor is mounted on the brake pedal bracket. Pressing the brake pedal
while the cruise control is engaged will disengage the cruise control system. The
BCM monitors the BPP sensor via the brake pedal position sensor signal circuit. The
BCM sends a GMLAN serial data message to the ECM indicating the position of the brake
pedal. For further information on the BPP sensor, refer to
Exterior Lighting Systems Description and Operation
in Lighting Systems.
The cruise control system will disengage when the cruise control on/off switch
is switched OFF.
The cruise control system will disengage when the ECM detects that a driver
override function has been active for approximately 60 seconds.
When the cruise control system has been disengaged, the ECM sends a GMLAN serial
data message to the IPC in order to turn off the Cruise indicator.
The vehicle speed stored in the memory of the ECM will be erased when the cruise
control on/off button is turned OFF, or the ignition switch is turned OFF.
Cruise Control Inhibited
The ECM inhibits the cruise control operation when any of the following conditions
exist:
• | A cruise control system DTC has been set. |
• | The vehicle speed is less than 40.2 km/h (25 mph). |
• | The vehicle speed is too high. |
• | The vehicle is in PARK, REVERSE, NEUTRAL, or 1st gear. |
• | The engine RPM is too low. |
• | The engine RPM 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. |
Cruise Control Description and Operation 3.5L
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 brake pedal position (BPP) sensor |
• | The body control module (BCM) |
• | The cruise control on/off switch |
• | The engine control module (ECM) |
| The + RES switch is the equivalent to an accel/resume switch. |
| the - SET switch is the equivalent to a set/coast switch. |
• | The throttle actuator control (TAC) module |
• | The vehicle speed sensor |
Cruise Control Engaged
The cruise control system will engage and adjust vehicle speeds, based on the
activation of the following cruise control switches:
The BCM monitors the signal circuit of the cruise control switches. The BCM
relays the cruise control switch status to the ECM via the GMLAN serial data circuit.
The ECM uses the status of the cruise control switch to determine when to capture
and maintain the vehicle speed. The ECM monitors the vehicle speed signal circuit
in order to determine and the desired vehicle speed. The ECM uses the TAC module and
the TAC motor in order to maintain the vehicle speed. For further review of the TAC
system, refer to
Throttle Actuator Control (TAC) System Description
in Engine Controls - 3.5L (LX9).
Ignition voltage is supplied to the cruise control switch from the 2-ampere
RUN/CRANK ELEC fuse located in the integrated BCM fuse block. The cruise control function
switches are arranged in a resistive ladder design, with each cruise control function
switch having a different resistance value. The BCM detects a specific voltage value
that is associated with any cruise control function switch being activated. When the
normally open cruise control on/off switch is turned ON, the switch closes and the
BCM detects a predetermined voltage signal on the cruise control set/coast and resume/accel
switch signal circuit. The BCM sends a GMLAN serial data message to the ECM indicating
that the on/off switch is active. Similarly, when the + RES switch or the - SET switch
are pressed, the BCM detects the predetermined voltage signal on the cruise control
set/coast and resume/accel switch signal circuit. To engage the cruise control system,
ensure that the vehicle speed is above 40.2 km/h (25 mph), turn the cruise on/off
switch ON and momentarily press the - SET switch. The ECM will engage the cruise control
system and record the vehicle speed. The ECM sends a GMLAN serial data message to
the instrument panel cluster (IPC) in order to illuminate the Cruise indicator in
the IPC. The - SET switch or the + RES switch will remain inactive when the BCM 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 switch and the + RES switch. When the
cruise control system is engaged, pressing and holding the - SET switch will allow
the vehicle to decelerate from the current set vehicle speed without deactivating
the cruise control system. When the - SET 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 switch will allow
the vehicle to decelerate at 1.6 km/h (1 mph) increments for each time
that the - SET is momentarily pressed, with a minimum vehicle speed of 37 km/h
(23 mph). Pressing and holding the + RES 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 + RES 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 + RES switch will allow
the vehicle to accelerate at 1.6 km/h (1 mph) increments for each time
that the + RES switch is momentarily pressed, with the maximum acceleration total
of 16 km/h (10 mph) over the current set vehicle speed. Momentarily
pressing the + RES 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 ECM disengages the cruise control operation based on the signals from the
following switches:
• | The cruise control on/off switch |
The BPP sensor is mounted on the brake pedal bracket. Pressing the brake pedal
while the cruise control is engaged will disengage the cruise control system. The
BCM monitors the BPP sensor via the brake pedal position sensor signal circuit. The
BCM sends a GMLAN serial data message to the ECM indicating the position of the brake
pedal. For further information on the BPP sensor, refer to
Exterior Lighting Systems Description and Operation
in Lighting Systems.
The cruise control system will disengage when the cruise control on/off switch
is switched OFF.
The cruise control system will disengage when the ECM detects that a driver
override function has been active for approximately 60 seconds.
When the cruise control system has been disengaged, the ECM sends a GMLAN serial
message to the IPC in order to turn off the Cruise indicator.
The vehicle speed stored in the memory of the ECM will be erased when the cruise
control on/off button is turned OFF, or the ignition switch is turned OFF.
Cruise Control Inhibited
The ECM inhibits the cruise control operation when any of the following conditions
exist:
• | A cruise control system DTC has been set. |
• | The vehicle speed is less than 40.2 km/h (25 mph). |
• | The vehicle speed is too high. |
• | The vehicle is in PARK, REVERSE, NEUTRAL, or 1st gear. |
• | The engine RPM is too low. |
• | The engine RPM 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. |