Cruise Control: Actuator
WARNING: This page is about a different car, the 1997 Lexus SC 300. However, it is still accessible from the selected car via links, so may be relevant.
Actuator consists of a bi-directional electric motor, magnetic clutch, potentiometer (rotary angle sensor) and control arm. Control arm is connected to actuator cable which moves the throttle plate. Electric motor responds to on-off duty cycle signals from the cruise control ECU. When motor operates, control arm moves. Cruise control ECU monitors the rotary angle of the control arm by applying a reference voltage to potentiometer.
A magnetic clutch connects the motor shaft to the control arm when the cruise control ECU turns the magnetic clutch on. If any of the following conditions occurs, the cruise control ECU turns the magnetic clutch off, disengaging the motor shaft from the control arm.
- Cruise main switch is turned off.
- CANCEL switch is turned on.
- COAST switch is turned on.
- Brake pedal or clutch pedal is pressed.
- Parking brake is applied.
- Vehicle speed decreases to less than 25 MPH.
- Difference between actual and set speeds is 10 MPH.
- Actuator motor malfunctions.
- Vehicle Speed Sensor (VSS) malfunctions.
- Circuit problem occurs.