Savana 2500 V8-6.6L DSL Turbo VIN 6 (2007)
Cruise Control: Description and Operation
Cruise Control Description and Operation (6.6L)
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:
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The accelerator pedal
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The engine control module (ECM)
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The ON/OFF switch
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The Resume/Accel switch
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The Set/Coast switch
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The torque converter clutch (TCC)/brake switch
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The stop lamp switch
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The throttle actuator control (TAC) module
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The vehicle speed sensor (VSS)
Cruise Control Engaged
The cruise control system will engage and adjust vehicle speed based on the activation of the following cruise control switches:
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ON/OFF
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Resume/accel
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Set/coast
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 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. Ignition positive voltage is supplied from the 10-amp IGN E fuse, to the cruise control
switch via the ignition 1 voltage circuit. When the normally open cruise control On/Off switch is turned ON, the switch closes and the engine control
module detects a high signal voltage on the cruise On/Off switch signal circuit. When the normally open Set/Coast switched is pressed, the switch closes
and the engine control module detects a high signal voltage on the Set/Coast signal circuit. To engage the cruise control system, the On/Off switch must
be ON and the set button momentarily pressed. The ECM will confirm that the cruise control enable criteria has been met. When the ECM determines
that the cruise control enable criteria has been met, the ECM will engage the cruise control system and record the selected vehicle speed. The ECM will
then send a class 2 message to the instrument panel cluster (IPC) in order to activate the cruise control 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 engine control module 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 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 engine control module 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 engine control module 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 engine control module.
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 On/Off switch
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The torque converter clutch (TCC)/brake switch
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The stop lamp switch
The TCC/brake switch and the stop lamp switch are used to disengage the cruise control. The stop lamp and TCC/brake switch are incorporated into an
assembly and are mounted to the brake pedal bracket. When the brake pedal is pressed, the normally closed TCC/brake switch opens and the normally
open stop lamp switch closes. The engine control module detects a low signal voltage on the TCC/brake signal circuit and detects a high signal voltage
on the stop lamp signal circuit. The vehicle speed stored in the memory of the engine control module will be erased when the cruise control On/Off
switch is turned OFF, or the ignition switch is turned OFF.
