Malibu L4-2.2L VIN F (2005)
Cruise Control: Description and Operation
CRUISE CONTROL DESCRIPTION AND OPERATION
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:
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The accelerator pedal
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The brake pedal position (BPP) sensor
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The body control module (BCM)
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The cruise control On/Off switch
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The engine control module (ECM)
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The + RES switch The + RES switch is the equivalent to an Accel/Resume switch.
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The - SET switch The - SET switch is the equivalent to a Set/Coast switch.
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The throttle actuator control (TAC) motor
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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:
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On/Off
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+ RES
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- SET
The body control module (BCM) monitors the signal circuit of the cruise control switches. The BCM relays the cruise control switch status to the
engine control module (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 traction control module (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 Computers and Control Systems - 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 serial 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 engine control module (ECM) disengages the cruise control operation based on the signals from the following switches:
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The brake pedal position (BPP) sensor
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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 body control module (BCM) monitors the BPP sensor via the BPP 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.