Automatic Speed Control Device (ASCD)
System DescriptionPOWER SUPPLY AND GROUND
When the ignition switch is in the ON or START position, power is supplied:
- through 10 A fuse [No. 8, located in the fuse block (J/B)]
- to ASCD control unit terminal (5).
Ground is supplied:
- to ASCD control unit terminal 17
- through body grounds (M2) and (M61).
When ASCD main switch is depressed (ON), ground is supplied:
- to ASCD control unit terminal (24)
- through ASCD steering switch terminal (13) and
- to ASCD control unit terminal (11)
- through ASCD steering switch terminal (14) and then CRUISE indicator illuminates.
OPERATION
Set Operation
To activate the ASCD, all of following conditions must exist:
- ASCD control unit receives ASCD main switch ON signal
- Power supply to ASCD control unit terminal (8) [Brake and clutch pedal are released (M/T models), or brake pedal is released and A/T selector lever is in other than P and N position (A/T models).]
- Vehicle speed is between 48 km/h (30 MPH) and 144 km/h (89 MPH). (Signal from combination meter)
When the SET/COAST switch is pressed, ASCD control unit receives SET/COAST signal and then ASCD pump is activated to control throttle wire and SET indicator illuminates.
A/T Overdrive Control during Cruise Control Driving
When the RESUME/ACCEL switch is pressed, a signal is sent:
- From ASCD control unit terminal (10)
- To TCM (transmission control module) terminal 24.
When this occurs, the TCM (transmission control module) cancels overdrive. When the RESUME/ACCEL switch is released, overdrive is reactivated.
In RESUME mode when vehicle speed is approximately 3 km/h (2 MPH) below memory speed, overdrive is reactivated.
Coast Operation
When the SET/COAST switch is pressed during cruise control driving, ASCD actuator returns the throttle cable to decrease vehicle set speed until the switch is released. Then the ASCD will keep the new set speed.
If SET/COAST switch is pressed and released quickly during cruise control driving, vehicle set speed will be reduced by 1.6 km/h (1 MPH).
Accel Operation
When the RESUME/ACCEL switch is pressed during cruise control driving, ASCD actuator pulls the throttle cable to increase vehicle set speed until the switch is released. Then the ASCD will keep the new set speed.
If RESUME/ACCEL switch is pressed and released quickly during cruise control driving, vehicle set speed will increase by 1.6 km/h (1 MPH).
Cancel Operation
When any of following condition exists, cruise operation will be canceled:
- CANCEL switch is pressed.
- Brake pedal is pressed. (Power supply to ASCD control unit terminal (23) from stop lamp switch)
- Brake or clutch pedal is pressed (M/T models), or brake pedal is pressed or A/T selector lever is shifted to P or N position. (Power supply to ASCD control unit terminal (8) is interrupted.)
If MAIN switch is turned to OFF when ASCD is activated, all of ASCD operation will be canceled and vehicle speed memory will be erased.
Resume Operation
When the RESUME/ACCEL switch is pressed after cancel operation other than pressing MAIN switch is performed, vehicle speed will return to last set speed. To resume vehicle set speed, vehicle condition must meet following conditions:
- Brake pedal is released.
- Clutch pedal is released. (M/T models)
- A/T selector lever is in other than P and N position. (A/T models)
- Vehicle speed is between 48 km/h (30 MPH) and 144 km/h (89 MPH).
ASCD PUMP OPERATION
The ASCD pump consists of a vacuum motor, an air valve and a release valve. When the ASCD activates, power is supplied:
- from ASCD control unit terminal (12)
- to ASCD pump terminal (1).
Ground is supplied to vacuum motor, air valve and release valve from ASCD control unit depending on the operated condition as shown in the table.
The pump is connected to ASCD actuator by vacuum hose. When the ASCD pump is activated, the ASCD pumps vacuum to the diaphragm of ASCD actuator to control throttle cable.