System Description

System Diagram:

SYSTEM DESCRIPTION

1. CRUISE CONTROL SYSTEM DESCRIPTION

The cruise control system is controlled by the ECM, and is activated by the throttle position sensor and motor. The ECM controls the following functions: ON-OFF, SET/COAST, RESUME/ACCEL, CANCEL, vehicle speed operation, motor output control, and overdrive control.

- The ECM compares the speed sensor vehicle speed with the stored vehicle speed set through the cruise control main switch. The ECM instructs the throttle valve motor of the throttle position sensor to close the valve when the driving vehicle speed is greater than the stored vehicle speed, and instructs it to open the valve when the driving speed is less than the stored speed.
- The ECM receives signals such as ON-OFF, SET/COAST, RESUME/ACCEL, and CANCEL from the cruise control main switch and executes them.
- The ECM illuminates the combination meter's CRUISE main indicator lamp when it receivers the cruise control main switch ON signal.
- The ECM cancels the cruise control system when the brake pedal is depressed and the ECM receives the stop lamp switch signal.
- The ECM cancels the cruise control system when the shift lever is moved from D (5th, 4th, 3rd, 2nd or 1st gear) to N, and the ECM receives the PNP switch signal.

2. LIMIT CONTROL

a. Low speed limit

The lowest possible limit of the speed setting range is set at approximately 40 km/h (25 mph). The cruise control system cannot be set when the vehicle speed is below the low speed limit. Cruise control operation will be automatically canceled and the stored vehicle speed will be erased when the vehicle speed decreases below the low speed limit while the cruise control system is operating.

b. High speed limit

The highest possible limit of the speed setting range is set at approximately 200 km/h (125 mph). The cruise control system cannot be set when the vehicle speed is over the high speed limit. Also, RESUME/ACCEL cannot be used to increase speed beyond the high speed limit.

3. OPERATION OF CRUISE CONTROL

The cruise control main switch operates 7 functions: SET, COAST, TAP-DOWN, RESUME, ACCEL, TAP- UP, and CANCEL. The SET, TAP-DOWN and COAST functions, and the RESUME, TAP-UP and ACCEL functions are operated with the same switch. The cruise control main switch is an automatic return type switch which turns on only while pressing it in each arrow direction and turns off after releasing it.

a. SET control

Vehicle speed is stored and constant speed control is maintained when setting the switch to SET/ COAST while driving with the cruise control main switch ON (the CRUISE main indicator lamp is illuminated), and the vehicle speed is within the set speed range (between the low and high speed limits).

b. COAST control

The ECM changes the cruise control demanding throttle opening angle to 0 degrees and decelerates the vehicle when SET/COAST on the cruise control main switch is pressed and held while the cruise control system is operating. When the cruise control main switch is released from SET/COAST, the vehicle speed is stored and constant speed control is maintained.

HINT: *The throttle valve is not fully closed due to idle speed control, etc.

c. TAP-DOWN control

When tapping down on the cruise control main switch to SET/COAST (for approximately. 0.5 seconds) while the cruise control system is operating, the stored vehicle speed decreases each time by approximately 1.6 km/h (1.0 mph). When the cruise control main switch is released from SET/COAST and the difference between the driving and stored vehicle speed is more than 5 km/h (3 mph), the vehicle speed is stored and constant speed is maintained.

d. ACCEL control

The throttle valve motor of the throttle position sensor and motor is instructed by the ECM to open the valve when RESUME/ACCEL on the cruise control main switch is pressed and held while the cruise control system is operating. When the cruise control main switch is released from RESUME/ACCEL, the vehicle speed is stored and constant speed is maintained.

e. TAP-UP control

When tapping up on the cruise control main switch to RESUME/ACCEL (for approximately 0.5 seconds) while the cruise control system is operating, the stored vehicle speed increases each time by approximately 1.6 km/h (1.0 mph). However, when the difference between the driving and the stored vehicle speed is more than 5 km/h (3 mph), the stored vehicle speed does not change.

f. RESUME control

If the cruise control operation was canceled with the stop lamp switch or the CANCEL switch, and if driving speed is within the set speed range, setting the cruise control main switch to RESUME/ACCEL restores the vehicle speed memorized at the time of cancellation, and constant speed is maintained.

g. Manual cancel control

Performing any of the following cancels the cruise control system (the stored vehicle speed in the ECM is maintained).

- Depressing the brake pedal
- Moving the shift lever to any position except D (5th, 4th, 3rd, 2nd and 1st gear)
- Setting the cruise control main switch to CANCEL
- Turning the cruise control main switch OFF (the stored vehicle speed in the ECU is not maintained).