When TCS Is Active

Pressure Increasing Mode

If the ABS ECU determines that either front wheel is slipping due to abrupt acceleration, etc., ABS ECU commands TCS solenoid valve (OUT) to close and TCS solenoid valve to open. ABS ECU also energizes ABS motor to drive the pump. The pump then sucks fluid out of brake master cylinder through the TCS solenoid valve (IN) and the inlet valve, it then sends brake fluid through the outlet valve (IN) to appropriate wheel cylinder, increasing fluid pressure in that cylinder. See Fig 1 .

Fig 1: Pressure Increasing Mode (TCS Active)
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

Pressure Holding Mode

If the ABS ECU determines that brake fluid pressure has been increased to optimum level, it stops supplying power to the motor and the TCS solenoid valve (IN). This causes the pump to stop operation and the TCS solenoid valve (IN) to close. As a result, brake fluid pressure in the wheel cylinder is retained. See Fig 2 .

Fig 2: Pressure Holding Mode (TCS Active)
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

Pressure Reducing Mode

If the ABS ECU determines that wheel slipping has been prevented, it commands the TCS solenoid valve (OUT) to open. This causes brake fluid in the wheel cylinder to flow through the ABS solenoid valve (IN), check valve (2) and TCL solenoid valve (OUT) back to the master cylinder, reducing brake fluid pressure in the brake circuit. See Fig 3 .

Fig 3: Pressure Reducing Mode (TCS Active)
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.