Cruise Control Systems: Description

WARNING: Vehicle is equipped with Supplemental Inflatable Restraint (SIR) system. When servicing vehicle, use care to avoid accidental air bag deployment. SIR system related components are located in various locations throughout interior and exterior of vehicle, depending on application. Do not use electrical test equipment on or near these circuits. Before attempting ANY repairs involving steering column, instrument panel or related components, or If necessary, deactivate SIR system before servicing components. See AIR BAG SAFETY PRECAUTIONS and DISABLING & ACTIVATING AIR BAG SYSTEM in AIR BAG RESTRAINT SYSTEMS article in RESTRAINTS.

NOTE: For fuse locations, see FUSES & CIRCUIT BREAKERS article in ELECTRICAL.

System Outline

The cruise control system allows to travel at a constant speed, by the operation of the switch, without having to depress the accelerator pedal. In this system, the engine throttle valve opening angle is adjusted automatically to control the vehicle at a constant speed.

With the ignition SW turned to on, the current flows through the GAUGE fuse to TERMINAL 9 of the integration relay to terminal (A) 9 to Terminal (D) 2 of the combination meter and the current through the ECU-IG fuse flows to TERMINAL 9 of the cruise control ECU. See Fig 1 and Fig 2 .

Set Control
When the SET/COAST SW, see Figure, is operated while traveling with the main SW, ON the speed when the SW is operated to OFF (SW released) is memorized, and the vehicle speed is controlled at that speed.
Coast Control
When the SET/COAST SW is operated to ON, the motor in the actuator rotates the throttle valve until it is closed fully to decrease the vehicle speed, and the speed when the SW is operated to OFF is memorized, and the vehicle speed is controlled at that speed. Furthermore, every time the SET/COAST SW is operated momentarily (Approximately 0.5 sec.) to ON, the memorized vehicle speed is decreased by approximately 1.5km/h.
Accel Control
When the RESUME/ACCEL SW, is operated to ON, the motor in the actuator rotates the throttle valve to open direction to increase the vehicle speed, and the speed when the SW is operated to OFF is memorized, and the vehicle speed is controlled at that speed. Furthermore, every time the RESUME/ACCEL SW is operated momentarily (Approximately 0.5 sec.) to ON, the memorized vehicle speed is increased by approximately 1.5km/h.
Manual Cancel Mechanism
If any of the following signals are input during cruise control traveling, the magnetic clutch of the actuator is turned off, and the current to the motor flows in the direction to close the throttle valve, and cancel the cruise control.
1. Stop lamp SW is ON (Brake pedal is depressed).
2. The CANCEL SW of the control SW is ON.
3. MAIN SW is OFF.
Resume Control
After canceling the cruise control (Except when the main SW is OFF) if the vehicle speed is above the minimum speed limit (Approximately 40km/h, 25mph), operating the RESUME/ACCEL SW from OFF to ON will cause the system to accelerate and resume to the vehicle speed before manual cancellation.
Overdrive Function
The overdrive may be cut on an uphill grade, while traveling with the cruise control. After the overdrive is cut, if the vehicle speed, reaches the overdrive resume speed (Set speed minus 2 km/h), and if the system determines that the uphill grade has finished, the overdrive will resume after the overdrive timer operation.
Auto Cancel Operation
If any of the following conditions are detected, the set speed is erased and the control is canceled.
1. The motor does not operate
2. Short in the magnetic clutch
3. Disconnection in the magnetic clutch (Includes blown STOP fuse)
4. No vehicle speed signal input
5. The actual vehicle speed becomes slower than the minimum speed limit

Fig 1: Identifying ECU Terminals & Voltages (1 Of 2)

Fig 2: Identifying ECU Terminals & Voltages (2 Of 2)