Speed Control - Service Information
SPEED CONTROL - SERVICE INFORMATIONDESCRIPTION
WARNING: THE USE OF SPEED CONTROL IS NOT RECOMMENDED WHEN DRIVING CONDITIONS DO NOT PERMIT MAINTAINING A CONSTANT SPEED, SUCH AS IN HEAVY TRAFFIC OR ON ROADS THAT ARE WINDING, ICY, SNOW COVERED, OR SLIPPERY.
NOTE: A cable and a vacuum controlled servo are not used. This is a servo-less system.
The Speed Control System is fully electronically controlled by the Powertrain Control Module (PCM). Control of the Speed Control System is accomplished by a Speed Control Switch (1) which is located just above the Multifunction Switch (2). The Speed Control System also uses other components of the vehicle to accomplish its tasks. The five other major components used are as follows; The PCM, Accelerator Pedal Position Sensor, Kickdown Switch (Automatic Transmission), Throttle Body and the Clutch Pedal Position Switch (Manual Transmission). The Speed Control System is designed to operate at speeds above 25 MPH (40 km/h).
OPERATION
When speed control operation is requested by the Speed Control Switch. The Powertrain Control Module allows a set speed to be stored in its memory for speed control. To store a set speed, press either of the SET switch functions while the vehicle is moving, at a speed above 25 MPH (40 km/h). In order for the speed control to engage, the brakes cannot be applied, nor can the gear selector be indicating the transmission is in Park or Neutral.
The speed control can be disengaged manually by:
- Applying the brake pedal
- Pressing the speed control switch to OFF
- Depressing the clutch pedal (if equipped).
NOTE: Turning the Speed Control Switch OFF or turning OFF the ignition switch will erase the set speed stored in the PCM.
For added safety, the Speed Control System is programmed to disengage for any of the following conditions:
- An indication of Park or Neutral
- A rapid increase in RPM (indicates that the clutch has been disengaged)
- Excessive engine RPM (indicates that the transmission may be in a low gear)
- The speed signal increases at a rate of 10 MPH per second (indicates that the coefficient of friction between the road surface and tires is extremely low)
- The speed signal decreases at a rate of 10 MPH per second (indicates that the vehicle may have decelerated at an extremely high rate)
Once the speed control has been disengaged, pulling the Speed Control Switch forward into the RESUME position (when speed is greater than 30 MPH) restores the vehicle to the target speed that was stored in the PCM.
While the speed control is engaged, the driver can increase the vehicle speed by pushing the Speed Control Switch upward into the ACCEL,SET position.
The new target speed is stored in the PCM when the ACCEL,SET switch position is released. The PCM also has a "tap-up" feature in which vehicle speed increases at a rate of approximately 2 MPH for each momentary switch activation of the ACCEL,SET switch position.
A "tap down" feature is used to decelerate without dis-engaging the Speed Control System. To decelerate from an existing recorded target speed, momentarily push the speed control switch downward into the DECEL,SET switch position. For each switch activation, speed will be lowered approximately 1 MPH