System Outline

The cruise control system is a constant vehicle speed controller which makes it possible to automatically adjust the opening of the engine throttle valve without depressing the accelerator pedal, but by operating a switch on the instrument panel instead.

Set Operation
When the ON-OFF SW is turned on and the - SET SW is pushed and the vehicle speed is within the set limit (Approx. 40 km/h, 25 mph to 200 km/h, 124 mph), a signal is sent to TERMINAL CCS of the engine control module, and the vehicle speed at the time the - SET SW is released is stored in the ECU as the set speed.
Set Speed Control
During cruise control driving, the ECU compares the speed stored in the ECU with the actual vehicle speed received by TERMINAL SPD of the engine control module from the combination meter, and controls the throttle control motor to maintain the set speed.

When the actual speed is lower than the set speed, the ECU causes current to flow from TERMINAL M+ of the engine control module to TERMINAL 2 of the throttle control motor, then out TERMINAL 1 to TERMINAL M- of the engine control module. As a result, the motor in the throttle control motor is rotated to open the throttle valve to increase the vehicle speed. When the actual driving speed is higher than the set speed, current flows from TERMINAL M- of the ECU to TERMINAL 1 of the throttle control motor, then out TERMINAL 2 to TERMINAL M+ of the engine control module.

This causes the motor in the throttle control motor to rotate to close the throttle valve to decrease the vehicle speed.
Coast Control
During cruise control driving, while the - SET SW is held down, the throttle control motor is rotated to close the throttle valve and decrease the driving speed. The vehicle speed when the - SET SW is released is stored, and the vehicle continues at the new set speed.
Accel Control
During cruise control driving, while the + RES SW is turned held down, the throttle control motor is rotated to open the throttle valve and increase the driving speed.

The vehicle speed when the + RES SW is released is stored and the vehicle continues at the new set speed.
Resume Control
If the vehicle speed is approximately 40 km/h (25 mph) or above, and the cruise control was cancelled with the CANCEL SW, pushing the + RES SW will cause the vehicle to resume the speed that was set before the cancellation.
Manual Cancel Mechanism
If any of the following signals are input while driving with the cruise control on, the cruise control will be cancelled.

* Depressing the clutch pedal (Cruise control clutch SW off). "The signal is no longer received by TERMINAL D of the ECU"

* Placing the shift lever in positions other than the "D" position (Park/Neutral position SW not in "D" position) (A/T), depressing the brake pedal (Stop light SW on) (M/T). "A signal is sent to TERMINAL STP of the ECU"

* Pushing the CANCEL SW (CANCEL SW on). "A signal is sent to TERMINAL CCS of the ECU"

* Pushing the ON-OFF SW off. "A signal is sent to TERMINAL CCS of the ECU"
Tap-Up Control Function
When the difference between the actual vehicle speed and the set speed is less than 5 km/h (3 mph), the set speed can be increased in 1.6 km/h (1 mph) increments by momentarily pressing (0.5 seconds) the + RES SW.
Tap-Down Control Function
When the difference between the actual vehicle speed and the set speed is less than 5 km/h (3 mph), the set speed can be reduced in 1.6 km/h (1 mph) increments by momentarily pressing (0.5 seconds) the - SET SW.
Auto Cancel Function
1. If any of the following operating conditions occurs while driving with the cruise control on, the set speed is erased and the cruise control is released, (ON-OFF SW turns off).
  When this occurs, the ignition SW must be turned off once before the ON-OFF SW will turn on.
  
  * When an abnormality is found in the stop light SW input circuit.
  
  * When an abnormality is found in the cancel circuit.
2. If any of the following operating conditions occurs while driving with the cruise control on, the set speed is erased and the cruise control is released, (ON-OFF SW turns off).
  When this occurs, the cancel state is cleared and the ON-OFF SW can be operated again.
  
  * When an abnormality is found in any electronic throttle parts.
  
  * When an open circuit occurs in the stop light SW.
  
  * When there is a momentary interruption of the vehicle speed signal.
  
  * When there is a short circuit in the stop light SW.
3. If any of the following conditions occurs while driving with the cruise control on, the set speed is erased and the cruise control is released. (The power to the magnetic clutch is cut off until the - SET SW is turned "ON" again.)
  * When power to the cruise control system is momentarily cut off.
Overdrive Control Function
The overdrive control may be cancelled if the vehicle travels on a steep slope while driving with the CC on. After the overdrive control has been cancelled and it has been detected that the slope has finished, the vehicle will return to the overdrive control mode again.