Cruise Control Description and Operation 3.6L
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 engine control module (ECM) |
• | The throttle actuator control (TAC) motor |
• | The vehicle speed sensor (VSS) |
Cruise Control Engaged
The Cruise Control System will engage and adjust vehicle speeds, based on the activation of the following cruise control switches:
The engine control module (ECM) monitors the signal circuit of the cruise control switches. The ECM uses the cruise control set/coast and resume/accelerate switch signal circuit in order to determine when to capture and maintain the vehicle speed. The
ECM monitors the vehicle speed signal circuit in order to determine the vehicle speed. The ECM uses the throttle actuator control (TAC) motor in order to maintain the vehicle speed. For further review of the TAC System, refer to
Throttle Actuator Control (TAC) System Description
.
Ignition voltage is supplied to the cruise control switch from the 2-amp CRUISE SW fuse located in the instrument panel (I/P) 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 ECM detects a specific voltage value that is associated with the cruise control function switch being activated. When the normally open cruise control on/off switch is turned ON, the switch closes and the amber
cruise control on/off switch illuminates. The ECM also detects a predetermined voltage signal on the cruise control cruise control set/coast and resume/accel switch signal circuit indicating that the on/off switch is active. Similarly, when the normally open
RES + switch or the normally open SET - switch are activated, the ECM detects the predetermined voltage signal on the cruise control set/coast and resume/accel switch signal circuit. To engage the Cruise Control System, press the cruise on/off button On
and momentarily activate the SET - switch. The ECM will engage the Cruise Control System and the ECM will record the vehicle speed. The ECM sends a class 2 message to the instrument panel cluster (IPC) in order to activate the Cruise indicator.
The SET - switch or the RES + switch will remain inactive when the ECM 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, activating 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 vehicle will maintain the current vehicle speed as the new vehicle set speed. When the Cruise Control System is engaged, momentarily activating the SET - switch will allow the vehicle to decelerate at 1.6 km/h
(1 mph) increments for each time that the SET - switch is activated. The minimum vehicle speed for the tap down function is 37 km/h (23 mph). Activating 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 vehicle will maintain the current vehicle speed as the new vehicle set speed. When the Cruise Control System is engaged, momentarily
activating 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 pressed. The tap up function will only accelerate the vehicle a total of 16 km/h (10 mph) over
the current set vehicle speed . Momentarily activating the RES + switch will recall the previous vehicle speed, after the Cruise Control System is disengaged by pressing the brake pedal or activating the CANCEL switch.
Cruise Control Disengaged
The engine control module (ECM) disengages the cruise control operation based on the signals from one of the following:
• | The brake pedal position (BPP) sensor |
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 brake pedal position sensor signal
circuit. The ECM detects a high voltage signal on stop lamp switch signal circuit from the BCM indicating that the brake pedal has been pressed. For further information on the BPP, refer to
Exterior Lighting Systems Description and Operation
and to
Brake Pedal Position Sensor Calibration
.
The Cruise Control System will also disengage when the cruise control on/off switch is switched OFF, or the cruise control cancel switch is activated. 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 a high signal voltage on the cruise control cancel switch 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. The Cruise Control System will disengage when the ECM detects that a driver override function has been active for approximately 60 seconds. When Cruise Control System has been disengaged, the ECM sends a class 2 message
to the instrument panel cluster (IPC) in order to turn off the Cruise indicator.
When the cruise control on/off switch is turned OFF, the Cruise Control System will disengage.
The Cruise Control System will disengage when the ECM detects that a driver override function has been active for approximately 60 seconds.
When Cruise Control System has been disengaged, the ECM sends a class 2 message to the instrument panel cluster (IPC) in order to turn off the Cruise indicator.
The vehicle speed stored in the memory of the ECM will be erased when the Off button is activated, or the ignition switch is turned OFF.
Cruise Control Inhibited
The engine control module (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 within 9-16 volts. |
• | The Traction Control System (TCS) is active for more than 2 seconds. |
Cruise Control Description and Operation 3.8L
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 powertrain control module (PCM) |
• | The throttle actuator control (TAC) module |
• | The vehicle speed sensor (VSS) |
Cruise Control Engaged
The Cruise Control System will engage and adjust vehicle speeds, based on the activation of the following cruise control switches:
The powertrain control module (PCM) monitors the signal circuit of the cruise control switches. The PCM uses the cruise control set/coast and resume/accelerate switch signal circuit in order to determine when to capture and maintain the vehicle speed.
The PCM monitors the vehicle speed signal circuit in order to determine the vehicle speed. The PCM uses the throttle actuator control (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
.
Ignition voltage is supplied to the cruise control switch from the 2-amp CRUISE fuse located in the instrument panel (I/P) 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 PCM detects a specific voltage value that is associated with the cruise control function switch being activated. When the normally open cruise control on/off switch is turned ON, the switch closes and the amber cruise
control on/off switch illuminates. The PCM also detects a predetermined voltage signal on the cruise control cruise control set/coast and resume/accel switch signal circuit indicating that the on/off switch is active. Similarly, when the normally open RES +
switch or the normally open SET - switch are activated, the PCM detects the predetermined voltage signal on the cruise control set/coast and resume/accel switch signal circuit. To engage the Cruise Control System, turn the Cruise Control System ON by momentarily
activating the cruise on/off button On and momentarily activating the SET - switch. The PCM will engage the Cruise Control System and the TAC module will record the vehicle speed. The PCM sends a class 2 message to the instrument panel cluster (IPC)
in order to activate the Cruise indicator. The SET - switch or the RES + switch will remain inactive when the ECM 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, activating 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 vehicle will maintain the current vehicle speed as the new vehicle set speed. When the Cruise Control System is engaged, momentarily activating the SET -
switch will allow the vehicle to decelerate at 1.6 km/h (1 mph) increments for each time that the SET - switch is activated. The minimum vehicle speed for the tap down function is 37 km/h (23 mph). Activating 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 vehicle will maintain the current vehicle speed as the new vehicle
set speed. When the Cruise Control System is engaged, momentarily activating 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 pressed. The tap up function will only accelerate
the vehicle a total of 16 km/h (10 mph) over the current set vehicle speed . Momentarily activating the RES + switch will recall the previous vehicle speed, after the Cruise Control System is disengaged by pressing the brake pedal or activating
the CANCEL switch.
Cruise Control Disengaged
The powertrain control module (PCM) disengages the cruise control operation based on the signals from one of the following:
• | The brake pedal position (BPP) sensor |
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 brake pedal position sensor via the BPP sensor signal
circuit. The PCM detects a high voltage signal on stop lamp switch signal circuit from the BCM indicating that the brake pedal has been pressed. For further information on the BPP sensor, refer to
Exterior Lighting Systems Description and Operation
and to
Brake Pedal Position Sensor Calibration
.
The Cruise Control System will also disengage when the cruise control on/off switch is switched OFF, or the cruise control cancel switch is activated. 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 a high signal voltage on the cruise control cancel switch signal circuit. The vehicle speed stored in the memory of the throttle actuator control (TAC) module will be erased when the Off button is activated,
or the ignition switch is turned OFF. The Cruise Control System will disengage when the PCM detects that a driver override function has been active for approximately 60 seconds. When Cruise Control System has been disengaged, the PCM sends a class 2
message to the instrument panel cluster (IPC) in order to turn off the Cruise indicator.
When the cruise control on/off switch is turned OFF, the Cruise Control System will disengage.
The Cruise Control System will disengage when the PCM detects that a driver override function has been active for approximately 60 seconds.
When Cruise Control System has been disengaged, the PCM sends a class 2 message to the instrument panel cluster (IPC) in order to turn off the Cruise indicator.
The vehicle speed stored in the memory of the throttle actuator control (TAC) module will be erased when the Off button is activated, or the ignition switch is turned OFF.
Cruise Control Inhibited
The powertrain control module (PCM) 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 within 9-16 volts. |
• | The Traction Control System (TCS) is active for more than 2 seconds. |