Cruise Control: Description and Operation

Current is applied at all times through STOP Fuse to TERMINAL 2 of the Stop Light SW and also through ECU-B Fuse to TERMINAL 1 of Cruise Control ECU.

With the Ignition SW turned to ON, the current flows through GAUGE Fuse to TERMINAL D-3 of Combination Meter and the current through ECU-IG Fuse flows to TERMINAL 9 of Cruise Control ECU.

When the Ignition SW is ON and the Cruise Control Main SW is turned ON, a signal is input from TERMINAL 5 of Cruise Control SW to TERMINAL 11 of Cruise Control ECU. As a result, the Cruise Control ECU functions and the current flows from the ECU-IG Fuse to TERMINAL 9 of Cruise Control ECU to TERMINAL 16 --> GROUND. and the Cruise Control system is in a condition ready for operation.

At the same time, the current through the GAUGE Fuse flows to TERMINAL D-3 of Cruise Control Indicator Light --> TERMINAL A-4 --> TERMINAL 4 of Cruise Control ECU --> TERMINAL 16 --> 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 SW is turned ON and the set SW is pushed with the vehicle speed within the set limit (approx. 40 kph, 25 mph to 200 kph, 124 mph), a signal is input to TERMINAL 10 of the Cruise Control ECU and the vehicle speed at the time the set SW 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 12 of the Cruise Control ECU from the Speedometer 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 15 of the Cruise Control ECU --> TERMINAL 1 of Cruise Control Actuator --> TERMINAL 2 -->TERMINAL 7 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 7 of ECU --> TERMINAL 2 of Cruise Control Actuator --> TERMINAL 1 --> TERMINAL 15 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 SW 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 SW is turned OFF is memorized and the vehicle continues at the new set speed.

4. ACCEL CONTROL
During Cruise Control driving, while the Accel SW 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 SW 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 kph, 25 mph) after canceling the set speed by the cancel SW, pushing the resume SW 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, current flow to Magnetic Clutch of the Actuator is cut OFF and the Motor rotates to close the Throttle Valve and the Cruise Control is released.

* Placing the Shift Lever in except 'D' position [Park/Neutral position SW except "D" position]. "Signal is not input to TERMINAL 3 of ECU"
* Depressing the Brake Pedal (Stop Light SW ON). "Signal input to TERMINAL 2 of ECU"
* Pull the cancel SW (Cancel SW ON). "Signal input to TERMINAL 10 of ECU"
* Pushing the Main Switch (Main SW OFF). "Signal input to TERMINAL 11 of the ECU"

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 Magnetic Clutch is stopped and the Cruise Control is released. (Main SW turns OFF).
When this occurs, the Ignition SW must be turned OFF once before the Main SW will turn ON.
* Motor does not operate despite the Motor drive signal being output.

B. If any of the following operating conditions occurs during Cruise Control operation, the set speed is erased, Current flow to Magnetic Clutch is stopped and the Cruise Control is released. (Main SW turn OFF)
When this occurs, the cancel state is cleared as the Main SW will turn ON again.
* Over current to transistor driving motor and/or the magnetic Clutch.
* Open Circuit in the Magnetic Clutch
* Momentary interruption of vehicle speed signal
* Short circuit in the Cruise Control SW
* When the vehicle speed has fallen more than 16 kph (10 mph) below the set speed. e.g. on an upward slope.

C. If any of the following conditions occurs during Cruise Control operation, 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 ON again)
* When the vehicle speed falls below the minimum speed limit, approx. 40 kph (25 mph)
* When power to the Cruise Control system is momentarily cut off.

D. If any of the following conditions occurs during Cruise Control operation, the cruise control is released.
* Open circuit for TERMINAL 2 of Stop Light SW.

8. AUTOMATIC TRANSMISSION CONTROL FUNCTION
* In overdrive, if the vehicle speed becomes lower than the overdrive cut speed (set speed minus approx. 4 kph, 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, if vehicle speed becomes higher than the overdrive return speed (set speed minus approx. 2 kph, 1.2 mph) and the ECU judges by the signals from Actuator's Potentiometer that the upward slope has finished, overdrive is resumed after approximately 2 seconds.

* During Cruise Control driving, the Cruise control operation signal is output from the Cruise control ECU to the Engine control Module. Upon receiving this signal, the Engine control Module changes the shift pattern to Normal. To maintain smooth Cruise control operation (On a downward slope etc.), the lock-up release of the Transmission when the idling point of the throttle position is "ON" is forbidden.