Cruise Control System Operation Gas

For gasoline engine applications, the cruise control module maintains a desired vehicle speed under normal driving conditions.

The following items describe the typical operation of the cruise control module:

1. Before the cruise control system will operate, the cruise control module must see an input from the stoplamp switch by depressing the brake pedal.
2. The cruise ON/OFF switch must be in the ON position.
3. Press the SET button in order to activate the cruise control module.

The cruise control module stores the last vehicle speed input from the vehicle control module (VCM) into a memory.

4. Use the stepper motor (part of the cruise control module) in order to increase or decrease throttle position.

Throttle opening will vary depending upon the load (going up or down an hill) in order to maintain speed.

5. Turn the cruise ON/OFF switch to the OFF position or apply the brake in order to turn the cruise system OFF.

Cruise Control System Operation Diesel

For diesel engine applications, the powertrain control module (PCM) takes the place of the cruise control module.

The PCM operates in the following manner:

1. Turn the CRUISE ON/OFF switch to the ON position.
2. When the SET button is activated, the PCM stores the last vehicle speed input from the vehicle speed sensor (VSS) into a memory location.

The PCM controls the electronic fuel injection pump in order to maintain the vehicle speed stored in memory.

3. The PCM increases and decreases fuel injection position depending on the load (going up or down a hill) to maintain vehicle speed.
4. If the CRUISE ON/OFF switch is in the OFF position or the brake is applied, the PCM will turn the cruise control system off.