Sierra 3500 Denali 2WD V8-6.0L (2011)
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The cruise control On/Off switch
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The cruise control cancel switch
The body control module (BCM) determines when the cruise control cancel switch is activated. When the normally open cancel switch is closed, the
BCM detects the predetermined voltage signal on the cruise control function switch circuit. The BCM sends a GMLAN serial data message to the ECM
in order to disengage the cruise control system.
The stop lamp switch is mounted on the brake pedal bracket. When the brake pedal is applied, the normally open stop lamp switch closes. The ECM
monitors the stop lamp signal circuit through a discrete input and a GMLAN serial data message signal from the BCM indicating the brake status. When
both signals indicate the brake pedal is applied, the ECM will disengage the cruise control system.
The Cruise Control System will disengage when the cruise control on/off switch is switched OFF. 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.
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 instrument panel cluster (IPC) in order to turn OFF the
Cruise Engaged indicator, and to the driver information center (DIC) in order to turn OFF the CRUISE SET TO ### message.
Each time the Cruise Control System is disengaged, the ECM will keep track of the reason for system disengagement. The last 8 disengagement reasons
will be recorded within the ECM memory, and can be viewed with a scan tool.
Cruise Control Inhibited
The engine control module (ECM) inhibits the cruise control operation when any of the following conditions exist:
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The ECM has not detected a brake pedal activation from the body control module (BCM).
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A Cruise Control System DTC has been set.
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The vehicle speed is less than 40.2 km/h (25 mph).
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The vehicle speed is too high.
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The vehicle is in PARK, REVERSE, NEUTRAL, or 1st gear.
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The engine RPM is too low.
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The engine RPM is too high.
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The system voltage is not between 9-16 volts.
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The Antilock Brake System (ABS)/Traction Control System (TCS) is active for more than 2 seconds.