Cruise Control: Description and Operation

Current is applied at all times through the STOP fuse to TERMINAL 2 of the stop light SW and also through the ECU-B fuse to TERMINAL 1 of the cruise control ECU.

With the ignition SW turned to ON, current flows through the GAUGE fuse to TERMINAL (A) 9 of the cruise control indicator light and the current through the ECU-IG fuse flows to TERMINAL 9 of the cruise control ECU.

When the ignition SW is ON and the cruise SW is turned ON, a signal is input from TERMINAL 5 of the cruise control SW to
TERMINAL 10 of the cruise control ECU. As a result, the cruise control ECU functions and the current flows from the ECU-IG fuse to TERMINAL 9 of the cruise control ECU to TERMINAL 16 to GROUND, and the cruise control system is ready for operation.

At the same time, the current through the GAUGE fuse flows to TERMINAL (A) 9 of the cruise control indicator light to TERMINAL (B) 3 to TERMINAL 4 of the cruise control ECU to TERMINAL 16 to GROUND, which lights up the cruise control indicator light, indicating that the cruise control is ready for operation.

1. SET OPERATION
When the cruise 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 when 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 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 15 of the cruise control ECU to TERMINAL 1 of the cruise control actuator to TERMINAL 2 to TERMINAL 7 of the cruise control ECU. As a result, the motor in the cruise control actuator is rotated to open the throttle valve and pull the throttle cable to increase the vehicle speed.

When the actual vehicle speed is higher than the set speed, the current to the cruise control actuator flows from TERMINAL 7 of the ECU to TERMINAL 2 of the cruise control actuator to TERMINAL 1 to TERMINAL 15 of the cruise control ECU. This causes the motor in the cruise control actuator to rotate and close the throttle valve to return the throttle cable, thus decrease the vehicle speed.

3. COAST CONTROL
During the cruise control driving, while the coast SW is turned 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) afier canceling the set speed by the cancel SW, pushing the resume SW will resume the speed which was 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 to a position except "D" position (Park/Neutral position SW except "D" position). "Signal is not input to TERMINAL 3 of the ECU".

* Depressing the brake pedal (Stop light SW ON). "Signal input to TERMINAL 2 of the ECU".

* Pushing the cancel switch (Cancel SW ON). "Signal input to TERMINAL 10 of the ECU".

* Pushing the cruise switch OFF "Signal input to TERMINAL 11 of the ECU".

7. TAP-UP CONTROL FUNCTION
When the difference between the actual vehicle speed and the set speed is less than 5 kph (3 mph), the set speed can be increased 1.5 kph (0.9 mph) each time by operation the RES/ACC SW quickly, within approx. 0.5 seconds.

8. TAP-DOWN CONTROL FUNCTION
When the difference between the actual vehicle speed and the set speed is less than 5 kph (3 mph), the set speed can be lowered 1.5 kph (0.9 mph) each time by operating the SET/COAST SW quickly, within approx. 0.6 seconds.

9. AUTO CANCEL FUNCTION
A. If any of the following conditions are detected, the set vehicle speed memory is erased, and the cruise control is released. In addition, the power indicator will blink until the cruise SW is turned ON again, and the cruise SW will not accept further operations unless the ignition SW is turned ON again.

* When current continues to flow to the motor inside the actuator, in the throttle valve "OPEN" direction.
* The motor does not operate despite the motor drive signal being output.

B. If any of the following conditions are detected, the set vehicle speed memory is erased, and the cruise control is released. In addition, the power indicator will blink until the cruise SW is turned ON again, and the system can not be operated until the ignition SW is turned ON again.

* Over current to transistor driving the motor or the magnetic clutch.
* Open circuit in the magnetic clutch.
* Momentary interruption of vehicle speed signal.
* Short circuit in the cruise control SW.

C. If any of the following conditions are detected, the set vehicle speed memory is erased, and the cruise control is released. (Reset is accepted)

* When the vehicle speed falls below the minimum speed limit, approx. 40 kph (25 mph)
* When the power to the cruise control system is momentarily cut OFF.

10. AUTOMATIC TRANSAXLE 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 is increased to prevent reduction in the vehicle speed.

* After releasing the overdrive, if the 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 the actuator's potentiometer that the upward slope has finished, the overdrive is resumed after.

* 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 transaxle when the idling point of the throttle position is "ON" is forbidden.