ABS 5.3 (3-channel system) system description} · ABS operation}

ABS 5.3 (3-channel system) system description} ABS operation} The ABS control module receives a signal from In addition, whenevera trip is begun and the stop-jightswitch and the AC voltage signals a speed of 6 km/h is exceeded,a test from the four speed sensors. These signals programme is started.} The solenoid valves are converted into digital wheel-speedsignals and the pump motor are electrically actuated independentlyof each other by two micro- and checked. If a fault is detected, the control processors. The wheel slip (approximately module switchesthe ASS function off, the proportional to the computed vehicle reference ASS MIL is switched on and the fault is stored. speed) is formed from these wheel-speed signals. If vehicle deceleration and excess slip at a Function of tile individualcomponentson wheel are detected, the pressure-holdingphase Page 45 -D 11 is initiated as the first step, i.e. the inlet valve for the relevantwheel is closed to prevent a further increase in pressure. If in spite of the pressure being held constant the wheel tends to continue to lock up, the pressure in the wheel cylinder is reduced. For this purpose, the outlet valve is opened and the brake fluid is pumped back to the master brake cylinder via the return pump (pressure-reductionphase)until the wheel turns again.} Then, depending on the control cycle, further appropriate cycles are initiated. This function and the input signals are continuouslymonitored. If a fault is detected, the control module switches the ABS function off, switches on the ABS MIL and stores the fault in a non-volatilememory in the control module. 45 -D 6