Cruise Control: Description and Operation

Current is applied at all times through stop fuse to TERMINAL A-2 of the control ECU TERMINAL 2 of stop light switch, and also through the ECU-B to TERMINAL A-6 of Cruise Control ECU.

With the Ignition switch turned to ON, the current flow through gauge fuse to TERMINAL A-1 of Combination Meter and the current through ECU-IG fuse flows to TERMINAL A-1 of Cruise Control ECU.

When the Ignition switch is ON and the Cruise Control main switch is turned ON, a signal is input from TERMINAL 15 of Cruise Control main switch to TERMINAL A-8 of Cruise Control ECU. As a result, the Cruise Control ECU functions and the current to TERMINAL A-1 of Cruise Control ECU to TERMINAL A-9 of Cruise Control ECU --> GROUND, and the Cruise Control system is in a condition ready for operation.

At the same time, the current through the gauge fuse flows from TERMINAL A-1 of Cruise Control indicator light --> TERMINAL C-2 TERMINAL B-6 of Cruise Control ECU TERMINAL A-9 --> to GROUND, causing the Cruise Control indicator light to light up, indicating that the Cruise Control is ready for operation.

1. SET OPERATION
When the Cruise Control main switch is turned ON and the set switch is pushed with the vehicle speed within the set limit (approx. 40 km/h, 2.5 mph to 200 km/h, 124 mph), a signal is input to TERMINAL B-8 of the Cruise Control ECU and the vehicle speed at the time the set switch is released is memorized in the ECU as the set speed.

2. SET SPEED CONTROL
During Cruise Control driving, the ECU compares the set speed memorized in the ECU with the actual vehicle speed input into TERMINAL A-7 of the Cruise Control ECU from the vehicle speed sensor (speed sensor), and controls the Cruise Control actuator to maintain the set speed.

When the actual speed is lower than the set speed, the ECU causes the current to the Cruise Control actuator to flow from TERMINAL B-4 --> TERMINAL 6 of Cruise Control actuator --> TERMINAL 7 --> TERMINAL B-10 of Cruise Control ECU. As a result, the motor in the Cruise Control actuator is rotated to open the throttle valve and the throttle cable is pulled to increase the vehicle speed. When the actual driving speed is higher than the set speed, the current to Cruise Control actuator flows from TERMINAL B-10 of ECU --> TERMINAL 7 of Cruise Control actuator --> TERMINAL 6 --> TERMINAL B-4 of Cruise Control ECU.

This causes the motor in the Cruise Control actuator to rotate to close the throttle valve and return the throttle cable to decrease the vehicle speed.

3. COAST CONTROL
During the Cruise Control driving, while the coast switch is ON, the Cruise Control actuator returns the throttle cable to close the throttle valve and decrease the driving speed, the vehicle speed when the coast switch is turned OFF and is memorized and the vehicle continues at the new set speed.

4. ACCEL CONTROL
During Cruise Control driving, while the accel switch is turned ON, the Cruise Control actuator pulls the throttle cable to open the throttle valve and increase the driving speed.

The vehicle speed when the accel switch is turned OFF is memorized and the vehicle continues at the new set speed.

5. RESUME CONTROL
Unless the vehicle speed falls below the minimum speed limit (approx. 40 km/h, 25 mph) after cancelling the speed by the cancel switch, pushing the resume switch will cause the vehicle to resume the speed set before cancellation.

6. MANUAL CANCEL MECHANISM
If any of the following operations occurs during Cruise Control operation, the Magnetic Clutch of the actuator turns OFF and the motor rotates to close the throttle valve and the Cruise Control is released.

* Placing the shift lever in "N" position (Park/Neutral position SW (neutral start SW) ON). "Signal input to TERMINAL A-4 of ECU"
* Depressing the brake pedal (stop light switch ON). "Signal input to TERMINAL A-3 of ECU"
* Depressing the parking brake pedal (parking brake switch ON). "Signal input to TERMINAL A-5 of ECU"
* Push the cancel switch (cancel switch ON)."Signal input to TERMINAL B-8.

7. AUTO CANCEL FUNCTION
a. If any of the following operating conditions occurs during Cruise Control operation, the set speed is erased, current flow to safety Magnetic Clutch is stopped and the Cruise Control is released. (Main switch turns OFF). When this occurs, the Ignition switch must be turned OFF once before the main switch will turn ON.

* Over current to transistor driving motor and/or Magnetic Clutch.
* When current continued to flow to the motor inside the actuator in the throttle valve "open" direction.
* Open circuit in Magnetic Clutch.
* Momentary interruption of vehicle speed signal.
* The resume switch is already on when the main switch is turned on.
* Short circuit in Cruise Control switch.
* Motor does not operate despite the motor drive signal being output.

b. If any of the following conditions occurs during Cruise Control operation, the set speed is erased and the Cruise Control is released. (the power of safety Magnetic Clutch is cut OFF until the set switch is "ON" again.)

* When the vehicle speed falls below the minimum speed limit. approx. (40 km/h (25 mph)
* When the vehicle speed falls more than 16 km/h (10 mph) below the set speed, e.g. on an upward slope.
* When power to the Cruise Control system is momentarily cut OFF.

c. If any of the following conditions occurs during Cruise Control operation. the Cruise Control is released.

* Open circuit for TERMINAL A-2 of Cruise Control ECU and splice point "I120".

8. AUTOMATIC TRANSMISSION CONTROL FUNCTION
* In overdrive. IF the vehicle speed becomes lower than the overdrive cut speed (set speed minimum approx. 4 km/h, 2.5 mph) during Cruise Control operation, such as driving up a hill, the overdrive is released and the power increased to prevent a reduction in vehicle speed.

* After releasing the overdrive, vehicle speed becomes higher than the overdrive return speed (set speed minimum approx. 2 m/h, 1.2 mph) and the ECU judges by the signals from potentiometer of the actuator that the upward slope has finished, overdrive is resumed after approximately 6 seconds.

* During Cruise Control driving, the Cruise Control operation signal is output from the Cruise Control ECU to the engine control module (engine and Electronic Controlled Transmission ECU). Upon receiving this signal, the engine control module (engine and Electronic Controlled Transmission ECU) changes the shift pattern to normal.

To maintain smooth Cruise Control operation (on a downward slope etc.), lock-up release of the transmission when the idling point of the throttle position is "ON" is forbidden.