Lucerne V8-4.6L (2008)
The ECM/PCM will disengage 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
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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 serial data message to the ECM/PCM in
order to disengage the cruise control system.
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 signal circuit as the voltage signal increases, while the pedal reaches the fully applied position. The BCM
sends a serial data message to the ECM/PCM indicating the position of the brake pedal. For more information on the BPP sensor, Refer to Exterior
Lighting Systems Description and Operation (See: Lighting and Horns/Description and Operation/Exterior Lighting Systems Description and Operation)
.
The Cruise Control System will also disengage when one of the following conditions exist:
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The cruise control On/Off switch is switched OFF.
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The ECM/PCM detects that a drive override function has been active for approximately 60 seconds.
When the Cruise Control System has been disengaged, the ECM/PCM sends a serial data message to the instrument panel cluster (IPC) in order to turn
OFF the Cruise Engaged indicator. The vehicle speed stored in the memory of the ECM/PCM will be erased when the cruise control On/Off switch is
turned OFF, or the ignition switch is turned OFF.
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 ECM/PCM inhibits the cruise control operation when any of the following conditions exist:
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The ECM/PCM 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 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 vehicle speed 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.
