Section 249 (Cruise Control Systems): Description

WARNING: This page is about a different car, the 2002 Toyota MR2. 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

Current is applied at all times through the STOP fuse to TERMINAL 2 of the stop light SW and to TERMINAL 1. With the ignition SW turned on, the current flows through GAUGE fuse to TERMINAL (B) 10 of the cruise control indicator light. At the same time, the current through EFl 1 fuse flows to TERMINAL 5 of the EFl MAIN relay to TERMINAL 3 to TERMINAL (A) 16 of the engine control module and TERMINAL 1 of the mass air flow meter.

When the ignition SW is on and the cruise control SW, see Fig 1, is turned on, a signal is input from TERMINAL 2 of the cruise control SW to TERMINAL (A) 19 of the engine control module.

TERMINALS (C) 17, (C) 6, (D) 8, (D) 21 and (D) 31 to GROUND, and the cruise control system is ready for operation.

At the same time, the cruise control indicator light to light up, indicating that the cruise control is ready for operation.

SET OPERATION
When the cruise control SW, see Fig 1, is turned on and the set SW, seeFig 2 , is pushed with the vehicle speed within the set limit (Approx. 25 mph. (40 km/h) to 124 mph (200 km/h), a signal is input to terminal (A) 19 of the engine control Module (ECM) and the vehicle speed at the time the set SW is released is memorized in the ECM as the set speed.
SET SPEED CONTROL
During cruise control driving, the engine control module compares the set speed memorized in the engine control module with the actual vehicle speed input into TERMINAL (B) 22 of the engine control module from the combination meter, and controls the engine control module to maintain the set speed.

When the actual diving speed is lower than the set speed, the current flows from TERMINAL (D) 19 of the engine control module to TERMINAL 1 of the throttle control motor to TERMINAL 2 to TERMINAL (D) 29 of the engine control module to TERMINAL (D) 8 to GROUND. As a result, the throttle control motor causes the throttle valve to open and the throttle cable is pulled to increase the vehicle speed. When the actual driving speed is higher than the set speed, the current flows from TERMINAL (D) 29 of the engine control module to TERMINAL 2 of the throttle control motor to TERMINAL 1 to TERMINAL (D) 19 of the engine control module to TERMINAL (D) 8 to GROUND and the throttle control motor causes the throttle valve to close and return the throttle cable to decrease the vehicle speed.
COAST CONTROL
During cruise control driving, while the coast SW is ON, see Fig 2, the throttle control motor returns the throttle cable to close the throttle valve and decrease the driving speed. The vehicle speed when the coast SW is turned off is memorized and the vehicle continues at the new set speed.
ACCEL CONTROL
During cruise control driving, while the accel SW is turned on, the throttle control motor pulls the throttle cable to open the throttle valve and increase the driving speed.

The vehicle speed when the accel SW is turned off is memorized and the vehicle continues at the new set speed.
RESUME CONTROL : Unless the vehicle falls below the minimum speed limit (Approx. 40 km/h, (25 mph.) after cancelling the speed by the cancel SW, see Figure, pushing the resume SW, see Fig 4, will cause the vehicle to resume the speed set before cancellation.
MANUAL CANCELLING MECHANISM
If any of the following operations occurs during cruise control operation, the magnetic clutch of the actuator turns off and the motor rotates to close the throttle valve and the cruise control is released.
- When shifting the gear, a signal is input into TERMINAL (A) 7 of the engine control module.
- Depressing the brake pedal (Stop light SW on). "Signal is input to TERMINAL (B) 6 of the engine control module".
- Pushing the cancel Sw, see Figure, (Cancel SW on). "Signal is input to TERMINAL (A) 19 of the engine control module".
- Pushing the cruise SW off, see Fig 1. "Signal is input to TERMINAL (A) 19 of the engine control module".
TAP-UP CONTROL FUNCTION
When the difference between the actual vehicle speed and the set speed is less that 5 km/h (3 mph), the set speed can be increased 1.6 km/h (1 mph) each time by operating the RESUME/ACCEL SW quickly, within 0.6 seconds.

When the difference between the actual vehicle speed and the set speed is less that 5 km/h (3 mph), the set speed can be lowered 1.6 km/h (1 mph) each time by operating the SET/COAST SW quickly, within 0.6 seconds.
AUTO CANCEL FUNCTION
A) If any of the following operating conditions occurs during cruise control operation, the set speed is erased, cruise control is released. (Cruise control SW turns off).

When this occurs, the ignition SW must be turned off once before the main SW will turn on.
- Open circuit for TERMINAL (A) 18 of the engine control module and TERMINAL 3 of the stop light SW.
- Abnormality in the vehicle speed signal.
- Malfunction in the electronically controlled throttle parts.
B) If any of the following conditions occurs during cruise control operation, the set speed is erased and the cruise control is released.
- When the vehicle speed falls below the minimum speed limit (Approx. 40 km/h 25 mph).
- When the vehicle speed falls more than 16 km/h (10 mph) below the set speed, E.G. on an upward slope.

Fig 1: Identifying Cruise Control On & Off Button (Main Switch)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 2: Identifying Set/Coast Setting

Fig 3: Locating Instrument Panel Cruise Control Indicator Lamp

Fig 4: Identifying Res/Acc Setting