Standard Speed Control

The speed control system is integrated with the engine management system and uses fueling intervention to automatically maintain a set vehicle speed. When engaged, the system can also be used to accelerate the vehicle without using the accelerator pedal.

The speed control system comprises the following main components:

• '+' and '-' (SET/increase speed and decrease speed) switches - Located on right steering wheel switchpack
• 'RESUME' switch - Located on right steering wheel switchpack
• 'CANCEL' switch - Located on right steering wheel switchpack
• Clockspring
• Speed control warning indicator in the Instrument Cluster (IC).

The speed control system uses inputs from the following:

• Brake pedal switch
• Accelerator Pedal Position (APP) sensor
• Power Control Module (PCM)
• Anti-lock Brake System (ABS) control module.

The speed control is operated by the driver using only the switches on the right steering wheel switchpack. When speed control is active, the PCM regulates the output signals to the fuel injectors to adjust the fuel supply to maintain the set speed.

During speed control operation, the PCM controls the vehicle speed by adjusting the fuel injection duration and timing. When the accelerator pedal is pressed with speed control active, the APP sensor outputs the signal for the PCM. The PCM outputs a calculated throttle angel signal in place of the actual throttle angle signal. The calculated throttle angle is derived from fuel demand based on the torque required to overcome the rolling resistance (vehicle motion drag).

The minimum set speed for speed control is 32 km/h (20 mph).

Speed control is automatically suspended if the following conditions apply:

• Vehicle speed falls is less than 24 km/h (15 mph).
• The brake pedal is pressed.
• The 'CANCEL' switch is operated.
• Neutral, park or reverse gear is selected.
• The Electric Park Brake (EPB) is applied.
• There is a large difference between actual speed and the set speed.
• If the accelerator pedal is used to accelerate beyond the set speed for more than 5 minutes.
• The Anti-lock Brake System (ABS) stores a Diagnostic Trouble Code (DTC).
• System error causes shut-off.
• All Terrain Progress Control (ATPC) is selected.

There are 4 standard speed control switches located on the right steering wheel switchpack:

• Set speed 'SET +' (increase set speed) switch
• Decrease speed '-' switch
• 'CANCEL' switch
• 'RESUME' switch.

The standard speed control switches are located on the right steering wheel switchpack. The switches are resistive ladder type switches which vary the resistance of a voltage signal sent to them. The resistive ladder is wired to a control module within the right steering wheel switchpack. The control module uses a Local Interconnect Network (LIN) to transmit the data to the Body Control Module/Gateway Module (BCM/GWM). The BCM/GWM sends the data on both the FlexRay and the High Speed (HS) Controller Area Network (CAN) chassis systems bus.

In the event of the PCM logging a speed control switch fault DTC, fault finding should start at the right steering wheel switchpack and clockspring. The PCM diagnostic detects that the right steering wheel switchpack has not provided an updated live counter.