Cruise Control: Description and Operation

With the Ignition SW turned to ON, the current flows through Gauge fuse to TERMINAL 7 of the Cruise Control indicator light. The current through ECU-IG fuse flows to TERMINAL 14 of the Cruise Control ECU. When the Ignition SW is ON and the Cruise Control SW is turned ON, a signal is input from TERMINAL 5 of Cruise Control SW to TERMINAL 19 of the Cruise Control ECU. As a result, the Cruise Control ECU functions and the current to TERMINAL 14 of the Cruise Control ECU flows to TERMINAL 13 --> Ground, and the Cruise Control system is ready for operation.
At the same time, the current through the Gauge fuse flows from TERMINAL 7 of Cruise Control indicator light --> TERMINAL 6 --> TERMINAL 7 of the Cruise Control ECU --> TERMINAL 13 --> 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. 36 kph, 23 mph to 200 kph, 124 mph), a signal is input to TERMINAL 18 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 20 of the Cruise Control ECU from the vehicle speed sensor (Comb. Meter), and controls the Cruise Control actuator to maintain the set speed.
When the actual vehicle speed is lower than the set speed, the ECU causes the current to the Cruise Control actuator to flow from TERMINAL 12 of the Cruise Control ECU --> TERMINAL 6 (3RZ-FE) or 1 (5VZ-FE) of Cruise Control actuator --> TERMINAL 7 (3RZ-FE) or 2 (5VZ-FE) --> TERMINAL 11 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 vehicle speed is higher than the set speed, the current to the Cruise Control actuator flows from TERMINAL 11 of the ECU --> TERMINAL 7 (3RZ-FE) or 2 (5VZ-FE) of Cruise Control actuator --> TERMINAL 6 (3RZ-FE) 1 (5VZ-FE) --> TERMINAL 12 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 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. 36 kph, 23 mph) after canceling the set speed by the cancel SW, pushing the resume SW will cause the vehicle to resume the vehicle speed set before cancellation.

6. MANUAL CANCEL MECHANISM
If any of the following operations occurs during Cruise Control operation, the safety 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 ON (A/T)) or Cruise Control clutch SW OFF (M/T)). "Signal Input To TERMINAL 2 of ECU"
^ Depressing the brake pedal (Stop Light SW ON). "Signal Input To TERMINAL 16 of ECU"
^ Pushing the cancel SW (Cancel SW ON). "Signal Input To TERMINAL 18 of 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 the safety 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.

^ Over current to transistor Driving motor And/Or safety magnetic clutch.

^ Current to control the Throttle valve in motor becomes always '"N".

^ Open circuit in safety magnetic clutch.

^ Momentary interruption of vehicle speed signal

^ Short circuit in Cruise Control SW.

^ 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 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 the vehicle speed falls more than 16 kph (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 condition occurs during Cruise Control operation, the Cruise Control is released. But in this case, the set speed is not erased. If the vehicle speed is more than the minimum speed limit (Approx. 40 kph 25 mph), Cruise Control operation is possible using 'Set' or 'Resume' on the control SW.

^ Open circuit for TERMINAL 10 of Cruise Control ECU and TERMINAL 3 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, vehicle speed becomes higher than the over drive return speed (Set Speed Minimum 2 kph, 1.2 mph), the ECU judges by the signals from potentiometer of the actuator that the upward slope has finished, and overdrive is resumed after approximately 6 Seconds.