Speed Control

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

• '+' and '-' (set/accelerate and decelerate) steering wheel switches
• Resume switch
• Cancel switch
• Clock spring
• Speed control warning lamp.

The speed control system also uses inputs from the brake pedal switch, the APP sensor, the ECM and the ABS module.

The speed control is operated by the driver using only the steering wheel switches. When speed control is active, the ECM regulates the Pulse Width Modulation (PWM) signals to the fuel injectors to adjust the fuel supply as required to maintain the set speed.

During speed control operation, the ECM controls vehicle speed by adjusting fuel injection duration and timing. When the accelerator pedal is pressed with speed control active, the ECM outputs a calculated throttle angle signal in place of the actual throttle angle signals produced by the APP sensor. The calculated throttle angle is derived from fuel demand.

The minimum set speed for speed control is 20 mph (32 (km/h). Speed control is automatically suspended if the following conditions apply:

• Vehicle speed falls below 20 mph (32 km/h).
• The brake pedal is pressed
• The cancel button is pressed
• Neutral, park or reverse gear is selected
• The difference between actual speed and the set speed is too great
• When the vehicle speed reaches a maximum speed of 150 mph (240 kph)
• If the accelerator pedal is used to accelerate beyond the set speed for too long
• Stability control system intervention
• System error causes shut-off.