Traction Control System: Overview Mitsubishi Eclipse IV

ABS/TCL OPERATION SOUNDS AND SENSATIONS

During normal operation, the ABS/TCL makes several sounds that may seem unusual at first

1. A whining sound is caused by the ABS/TCL hydraulic unit motor.
2. When pressure is applied to the brake pedal, the pulsation of the pedal causes a scraping sound.
3. When the brakes are applied firmly, the ABS/TCL operates, rapidly applying and releasing the brakes many times per second. This repeated application and release of braking forces can cause the suspension to make a thumping sound and the tires to squeak.

The TCL is a system that has added the cut valve and suction valve to the conventional ABS system. These valves are used to control each of the road wheels independently. These differences include sounds, sensations, and vehicle performance that owners and service technicians who are not familiar with TCL may not be used to.

Some operational characteristics may seem to be malfunctions, but they are simply signs of normal TCL operation. When diagnosing the TCL system, keep these operational characteristics in mind. Inform the owner of the kind of performance characteristics to expect from a TCL-equipped vehicle.

CIRCUIT OPERATION

1. A toothed wheel speed rotor generates a voltage pulse as it moves across the pickup field of each wheel speed sensor.
2. The amount of voltage generated at each wheel is determined by the clearance between the wheel speed rotor teeth and the wheel speed sensor, and by the speed of rotation.
3. Sends alternating current signals at frequencies which are proportional to the rotation speeds of each wheel to the ABS electronic control unit (ABS/TCL-ECU).
4. The ABS hydraulic unit modulates the amount of braking force individually applied to each wheel cylinder.

1. A toothed wheel speed rotor generates a voltage pulse as it moves across the pickup field of each wheel speed sensor.
2. The amount of voltage generated at each wheel is determined by the clearance between the wheel speed rotor teeth and the wheel speed sensor, and by the speed of rotation.
3. Sends alternating current signals at frequencies which are proportional to the rotation speeds of each wheel to the ABS/TCL electronic control unit (ABS/TCL-ECU).
4. The ABS hydraulic unit modulates the amount of braking force to front wheel cylinders individually to activate the TCL system.

1. A toothed wheel speed rotor generates a voltage pulse as it moves across the pickup field of each wheel speed sensor.
2. The amount of voltage generated at each wheel is determined by the clearance between the wheel speed rotor teeth and the wheel speed sensor, and by the speed of rotation.
3. Sends alternating current signals at frequencies which are proportional to the rotation speeds of each wheel to the ABS electronic control unit (ABS/TCL-ECU).
4. The ABS hydraulic unit modulates the amount of braking force individually applied to each wheel cylinder.

1. A toothed wheel speed rotor generates a voltage pulse as it moves across the pickup field of each wheel speed sensor.
2. The amount of voltage generated at each wheel is determined by the clearance between the wheel speed rotor teeth and the wheel speed sensor, and by the speed of rotation.
3. Sends alternating current signals at frequencies which are proportional to the rotation speeds of each wheel to the ABS/TCL electronic control unit (ABS/TCL-ECU).
4. The ABS hydraulic unit modulates the amount of braking force to front wheel cylinders individually to activate the TCL system.

1. A toothed wheel speed rotor generates a voltage pulse as it moves across the pickup field of each wheel speed sensor.
2. The amount of voltage generated at each wheel is determined by the clearance between the wheel speed rotor teeth and the wheel speed sensor, and by the speed of rotation.
3. Sends alternating current signals at frequencies which are proportional to the rotation speeds of each wheel to the ABS electronic control unit (ABS/TCL-ECU).
4. The ABS hydraulic unit modulates the amount of braking force individually applied to each wheel cylinder.

1. A toothed wheel speed rotor generates a voltage pulse as it moves across the pickup field of each wheel speed sensor.
2. The amount of voltage generated at each wheel is determined by the clearance between the wheel speed rotor teeth and the wheel speed sensor, and by the speed of rotation.
3. Sends alternating current signals at frequencies which are proportional to the rotation speeds of each wheel to the ABS electronic control unit (ABS/TCL-ECU).
4. The ABS hydraulic unit modulates the amount of braking force to front wheel cylinders individually to activate the TCL system.

1. A toothed wheel speed rotor generates a voltage pulse as it moves across the pickup field of each wheel speed sensor.
2. The amount of voltage generated at each wheel is determined by the clearance between the wheel speed rotor teeth and the wheel speed sensor, and by the speed of rotation.
3. Sends alternating current signals at frequencies which are proportional to the rotation speeds of each wheel to the ABS electronic control unit (ABS/TCL-ECU).
4. The ABS hydraulic unit modulates the amount of braking force individually applied to each wheel cylinder.

1. A toothed wheel speed rotor generates a voltage pulse as it moves across the pickup field of each wheel speed sensor.
2. The amount of voltage generated at each wheel is determined by the clearance between the wheel speed rotor teeth and the wheel speed sensor, and by the speed of rotation.
3. Sends alternating current signals at frequencies which are proportional to the rotation speeds of each wheel to the ABS electronic control unit (ABS/TCL-ECU).
4. The ABS hydraulic unit modulates the amount of braking force to front wheel cylinders individually to activate the TCL system.

1. The ABS/TCL-ECU contains the power supply circuit (terminal 32) for the solenoid valve. The solenoid valve is energized by the valve relay, which is integrated in the ABS/TCL-ECU.
2. The valve relay, which is integrated in the ABS/TCL-ECU, is always energizing the solenoid valve unless the initial check is in progress when the ignition switch is turned on.
3. The ABS/TCL-ECU activates the solenoid valve by turning on its driving transistor.

1. The ABS/TCL-ECU contains the power supply circuit (terminal 1) for the pump motor. The pump motor is energized by the motor relay, which is integrated in the ABS/TCL-ECU.
2. The motor relay, which is integrated in the ABS/TCL-ECU, is always off unless the motor solenoid valve check is activated when the vehicle is started.
3. The ABS/TCL-ECU activates the pump motor by turning on the ECU built-in motor relay when the ABS is working.

1. The ABS/TCL-ECU contains the power supply circuit (terminal 32) for the solenoid valve. The solenoid valve is energized by the valve relay, which is integrated in the ABS/TCL-ECU.
2. The valve relay, which is integrated in the ABS/TCL-ECU, is always energizing the solenoid valve unless the initial check is in progress when the ignition switch is turned on.

The ECM < M/T > or PCM < A/T > communicates with the ABS/TCL-ECU via CAN bus lines, and sends the data from each ECU.

The ABS/TCL-ECU is energized by the ignition switch (IG1) through multi-purpose fuse 23 and the ABS/TCL-ECU terminal 4.

TECHNICAL DESCRIPTION (COMMENT)

If the scan tool (MUT-III Sub Assembly) cannot communicate with the ABS system, the CAN bus lines may be defective. If the ABS system does not work, the ABS/TCL-ECU or its power supply circuit may be defective.

1. The ABS/TCL-ECU is energized by the ignition switch (IG1) through multi-purpose fuse 23 and the ABS/TCL-ECU terminal 4.
2. If the power supply to the ABS/TCL-ECU has failed, scan tool (MUT-III Sub Assembly) will not be able to communicate with it.

1. The ABS/TCL-ECU sends the TCL OFF indicator and TCL indicator signals to the combination meter via the CAN communication.
2. This may be caused by faults in the CAN bus line, the combination meter, or the ABS/TCL-ECU.

ABS/TCL-ECU terminal 38 is grounded every time the TCL switch is pressed. ABS/TCL-ECU monitors this operation state and turns the TCL ON or OFF.