Section 249 (Cruise Control Systems - V8): Description

WARNING: This page is about a different car, the 2002 Toyota Tundra. However, it is still accessible from the selected car via links, so may be relevant.

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 is a constant vehicle controller which controls the opening angle of the engine throttle valve by the SW, and allows driving at a constant speed without depressing the accelerator pedal.

Set Control :
When the SET/COAST SW, see Fig 1, is operated while travelling with the main SW, see Fig 2, on, the speed when the SET/COAST SW is operated to off is memorized, and the vehicle speed is controlled at that speed.
Coast Control :
When the SET/COAST SW, see Fig 1, is operated to on, the cruise control opening angle requirement is turned to 0 to decrease the vehicle speed, and the speed when the SET/COAST 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 (Approx. 0.5 sec.) to on the memorized vehicle speed is decreased approximately 1.0 mph.
Accel Control :
when the RES/ACC SW, see Fig 3, is operated to on, the throttle motor rotates the throttle valve to open direction to increase the vehicle speed, and the speed when the RES/ACC SW, see Fig 3, is operated to off is memorized, and the vehicle speed is controlled at that speed.

Furthermore, every time the RES/ACC SW is operated momentarily (Approx. 0.5 sec.) to on the memorized vehicle speed is increased approximately 1.0 mph.
Manual Cancelling Mechanism :
If any of the following signals are input during cruise control traveling, the current to the motor flows in the direction to close the throttle valve, and cancel the cruise control.
- The stop light SW is turned on (Brake pedal is depressed).
- The CANCEL SW of the control SW is on.
- The CRUISE SW is off.
Resume Control : After cancelling the cruise control (except when the main switch is off) if the vehicle speed is above the minimum speed limit Approx. 25 mph operating the RES/ACC SW, see Fig 3, to on from off will cause the system to accelerate and resume to the vehicle speed before manual cancellation.
Overdrive Control Function
The overdrive may be cut on an uphill grade, while travelling with the cruise control.

After the overdrive is cut, if the vehicle speed reaches the overdrive resume speed (Set speed minus 1.2 mph) 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 cancelled.
- Disconnection and/or short in the stop light SW.
- Malfunction in the vehicle speed signal.
- Malfunction in the electronic throttle parts.
- Malfunction in the stop light SW input circuit.
- Malfunction in the cancel circuit.
- The actual vehicle speed becomes slower than the minimum speed limit.
- The actual vehicle speed becomes 10 mph slower than the set speed.

Fig 1: Identifying Set/Coast Setting

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 2: Identifying Cruise Control On & Off Button (Main Switch)

Fig 3: Identifying Res/Acc Setting