Cruise Control System
CRUISE CONTROL: CRUISE CONTROL SYSTEM: SYSTEM DIAGRAM
Communication Table
SYSTEM DESCRIPTION
1. CRUISE CONTROL SYSTEM
This system is controlled by the ECM and actuated by the throttle body. The ECM controls the following functions: ON-OFF, -SET, +RES, CANCEL, vehicle speed operation, throttle motor output control and shift down control.
The ECM compares the driving vehicle speed from the vehicle speed sensor with the stored vehicle speed set through the cruise control switch. The ECM controls the throttle motor of the throttle body to open the valve when the driving speed is less than the stored speed.
The ECM receives signals, such as ON-OFF, -SET, +RES and CANCEL, from the cruise control switch and executes the corresponding function.
The ECM illuminates the cruise control indicator light in the combination meter assembly when it receives the cruise control switch on signal.
The ECM illuminates the cruise control SET indicator light in the combination meter assembly when the cruise control system is operated by pushing the cruise control switch to -SET.
The ECM cancels cruise control when the brake pedal is depressed and the ECM receives the stop light switch signal.
The ECM cancels cruise control when the shift lever is moved from D to N or when 3rd, 2nd or 1st range is selected with the shift lever in S.
2. LIMIT CONTROL
(a) Low speed limit
The lower 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. The cruise control operation will be automatically canceled but the stored vehicle speed will be retained when the vehicle speed decreases below the low speed limit of 40 km/h (25 mph) while cruise control is in operation.
(b) High speed limit
The upper 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. Also, +RES cannot be used to increase speed beyond the high speed limit.
3. OPERATION OF CRUISE CONTROL
The cruise control switch is used to operate 7 functions: SET, COAST, TAP-DOWN, RES (RESUME), ACCELERATION, TAP-UP and CANCEL. The SET, TAP-DOWN and COAST functions and the RES (RESUME), TAP-UP and ACCELERATION functions are operated with the same switch. The cruise control switch is an automatic return type switch which turns on only while holding it in each direction and turns off after releasing it.
(a) SET CONTROL
The vehicle speed is stored and constant speed control is initiated when pushing the switch to -SET while driving with the cruise control switch on (the cruise control indicator light and cruise control SET indicator light is on) and with the vehicle speed within the set speed range (between the low and high speed limits).
(b) COAST CONTROL
When the cruise control switch is pushed to -SET and held in that position while the cruise control system is operating, the ECM sends a throttle valve opening angle 0° demand signal to the throttle body. Then, the vehicle speed is stored and maintained when the cruise control switch is released.
(c) TAP-DOWN CONTROL
When tapping down the cruise control switch to -SET (for approximately 0.6 seconds) while the cruise control system is in operation, the stored vehicle speed decreases each time by approximately 1.6 km/h (1 mph). However, when the difference between the driving and stored vehicle speeds is more than approximately 5 km/h (3 mph), the stored vehicle speed is set to the actual vehicle speed at the moment the cruise control switch is released from -SET and constant speed control is initiated.
(d) ACCELERATION CONTROL
The throttle motor of the throttle body is instructed by the ECM to open the throttle valve when the cruise control switch is pushed to +RES and held while the cruise control system is in operation. When the cruise control switch is released from +RES, the vehicle speed is stored and the vehicle is controlled in order to maintain a constant speed.
(e) TAP-UP CONTROL
When tapping up the cruise control switch to +RES (for approximately 0.6 seconds) while the cruise control system is in operation, the stored vehicle speed increases each time by approximately 1.6 km/h (1 mph). However, when the difference between the driving and the stored vehicle speed is more than approximately 5 km/h (3 mph), the stored vehicle speed will not be changed.
(f) RES (RESUME) CONTROL
If cruise control operation is canceled with the stop light switch, CANCEL switch, etc., and if the driving speed is within the set speed range, pushing the cruise control switch to +RES restores the vehicle speed memorized at the time of cancellation, and initiates constant speed control.
(g) SHIFT DOWN CONTROL (for Automatic Transmission)
Overdrive may be canceled automatically when using cruise control while driving on inclined roads, etc.
After overdrive is canceled, if the system determines that the road is no longer inclined based on the throttle valve opening amount, overdrive will be restored.
If overdrive is canceled during an ACCEL or RESUME operation, overdrive will be restored after the ACCEL or RESUME operation is completed.
(h) MANUAL CANCEL CONTROL
Performing any of the following cancels cruise control while the system is operating (the stored vehicle speed in the ECM is maintained).
Depressing the brake pedal
Pulling the cruise control switch to CANCEL
Driving the vehicle while the vehicle stability control system is operating
Turning the cruise control switch off (the stored vehicle speed in the ECM is not maintained)
When the ECM detects a cruise control cancel signal from the four wheel control ECU
Moving the shift lever from D to N, or selecting 3rd, 2nd or 1st range with the shift lever in S
4. AUTO CANCEL (FAIL-SAFE)
This system has an automatic cancellation function (fail-safe) Fail-Safe Chart.