TEVES MARK 20 ABS WITH TRACTION
CONTROL ABS BRAKING HYDRAULIC
CIRCUIT – SOLENOID AND SHUTTLE VALVE
FUNCTION
This hydraulic circuit diagram (Fig. 7) shows a
vehicle equipped with ABS and traction control in
the ABS braking mode. This hydraulic circuit (Fig.
7) shows a situation where one wheel is slipping
because the driver is attempting to stop the vehicle
at a faster rate than the surface the vehicle’s tires
are on will allow. The hydraulic shuttle valve (Fig. 7)
closes upon brake application so that the pump can
not suck brake fluid from the master cylinder. The
normally open and normally closed valves modulate
the brake hydraulic pressure as required. The pump/
motor is switched on so that the brake fluid from the
low pressure accumulators is returned to the master
cylinder circuits. The brake fluid will then be routed
to either the master cylinder or the wheel brake
depending on the position of the normally open
valve.
TEVES MARK 20 ABS WITH TRACTION
CONTROL– TRACTION CONTROL HYDRAULIC
CIRCUIT – SOLENOID AND SHUTTLE VALVE
FUNCTION
This hydraulic circuit diagram (Fig. 8) shows a
vehicle equipped with ABS and traction control in
the traction control mode. The hydraulic circuit (Fig.
8) shows a situation where a driven wheel is spin-
ning and brake pressure is required to reduce its
speed. The normally open ASR valve (Fig. 8) is ener-
gized to isolate the brake fluid being pumped from
the master cylinder and to isolate the driven wheel.
Also, the normally open ASR valve bypasses the
pump output back to the master cylinder at a fixed
pressure setting. The normally open and normally
closed valves (Fig. 8) modulate the brake pressure as
required to the spinning wheel.
Fig. 6 ABS With Traction Control Normal Braking Hydraulic Circuit
5 - 58
BRAKES
300M
DESCRIPTION AND OPERATION (Continued)