Cruise Control: Description and Operation

CRUISE CONTROL: CRUISE CONTROL SYSTEM: SYSTEM DESCRIPTION

SYSTEM DESCRIPTION

1. CRUISE CONTROL SYSTEM
The cruise control system makes it possible to drive at a desired speed without using the accelerator pedal.
The ECM controls the throttle opening angle based on signals from switches and sensors.
A microcomputer which controls the cruise control system is built into the ECM, and the actuator is the throttle body assembly (intake shutter assembly).
Constant speed control is ready to operate when the cruise control main switch ON-OFF button is pushed (the CRUISE main indicator light comes on).
Operating the cruise control main switch, the driver can control the following functions.
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 driving vehicle speed is below the low speed limit. Cruise control operation will be automatically canceled but the stored vehicle speed will be retained when the vehicle speed drops below the low speed limit 40 km/h (25mph) while the cruise control is in operation.
(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 driving vehicle speed is over the high speed limit. Speed up using + (ACCEL)/RES (RESUME) with the cruise control main switch assembly also cannot be set beyond the high speed limit.
3. OPERATION OF CRUISE CONTROL
The cruise control main switch operates seven 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 assembly is an automatic return type switch which turns on only while operating 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 the switch is released from - (COAST)/SET while driving with the cruise control main switch ON-OFF button on (the CRUISE main indicator light is on), and the vehicle speed is within the set speed range (between the low and high speed limits).
(b) COAST CONTROL
The ECM makes the cruise control demanding throttle opening angle zero degrees and decelerates the vehicle (the throttle valve is not fully closed due to idle speed control, etc.) when - (COAST)/SET on the cruise control main switch is pressed and held while the cruise control system is in operation. Vehicle speed, when the cruise control main switch is released from - (COAST)/SET, is stored and constant speed control is maintained.
(c) TAP-DOWN CONTROL
When tapping down on the cruise control main switch to - (COAST)/SET (for approx. 0.5 second) while the cruise control system is in operation, the stored vehicle speed decreases 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 (approx. 3.1 mph), the vehicle speed, when the cruise control main switch is released from - (COAST)/SET, will be stored and constant speed control is maintained.
(d) ACCELERATION CONTROL
The throttle valve motor of the throttle position sensor and motor is instructed by the ECM to open the valve when + (ACCEL)/RES (RESUME) on the cruise control main switch is pressed and held while the cruise control system is in operation. Vehicle speed, when the cruise control main switch is released from + (ACCEL)/RES (RESUME), is stored and the vehicle is controlled at a constant speed.
(e) TAP-UP CONTROL
When tapping up on the cruise control main switch to + (ACCEL)/RES (RESUME) (for approx. 0.5 second) while the cruise control system is in operation, 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 (approx. 3.1 mph), the stored vehicle speed will not be changed.
(f) RESUME CONTROL
If cruise control operation was canceled under the manual cancel condition (other than by turning cruise control main switch ON-OFF button off), and if driving speed is within the limit range, pushing the cruise control main switch to + (ACCEL)/RES (RESUME) restores vehicle speed memorized at the time of cancellation, and maintains constant speed control. Even when cruise control is canceled automatically due to the vehicle speed decreasing below the low speed limit, cruise control can be resumed when the vehicle speed returns to over the low speed limit ,since the stored vehicle speed remains in the memory.
(g) MANUAL CANCEL CONTROL
Doing any of the following cancels the cruise control system while in operation. (The stored vehicle speed in the ECM is maintained.)

- Depressing the brake pedal
- Depressing the clutch pedal (Manual Transaxle)
- Moving the shift lever to any position except D (Automatic Transaxle)
- Pushing the cruise control main switch to CANCEL
- Pushing the cruise control main switch ON-OFF button off (The stored vehicle speed in the ECM is not maintained.)

(h) OTHER CANCEL CONTROL
Cruise control will be halted if VSC starts operation while driving (Vehicle speed will be memorized).