Subaru SVX 1992 Manual page 847

BRAKES [M5B5] 4-4
4. ABS WARNING LIGHT
When a signal system or the electronic control unit
(E .C .U.) becomes inoperative, the warning light in the
instrument panel comes on to indicate that the system
or control unit is malfunctioning . At the same time,
current flowing through the hydraulic control unit is
interrupted so that the brake system functions as a
conventional brake system . The circuit through which
the warning light comes on utilizes a dual system
design.
If the warning light comes on upon detection of a
system malfunction, the control unit's LED also shows a
trouble code.
FWD
4
5
A
»
60 80 100
U , " 120
120
ATGU
®
40 -80 ~o
TEMP
2 O
® H
1
®
®
8
~
20 -40 ®
® 240=140
F
_ ¬ 9 0 k""' ° °
'16
0 y
X1000r/mIn
O MPH
PREMIUM UNLEADED FUEL ONLY
® STEER ~~
GNEGN
POWER
~U.
STOP
BRAKE AS
AIR BAG
d11G
ENGINE LAMP 0)
6)
L
Warning light
C4-560
Fig. 27
5. HYDRAULIC CONTROL UNIT
The hydraulic control unit is a fluid pressure control
assembly which consists of an electric motor, plunger
pump, damper, housing, magnet valve and relay . The
magnet valve moves to three positions, as shown in
Figure 28. When it is moved to position "1" (current
"OFF"), the master cylinder and brake system are con-
nected to each other. With the valve moved to position
"2" (part of current flow "ON"), all passages are closed .
At position "3" (full-current flow "ON"), master cylinder
ports are closed and the line between the hydraulic unit
reservoir is connected to the brake system .
As wheel deceleration exceeds the specified decelera-
tion setting during braking, the magnet valve moves to
position "2" to hold brake fluid pressure . Further decel-
eration increases moves the magnet valve to position
"3" so that brake fluid pressure is released and, at the
same time, the motor starts to drive the plunger pump .
When wheel deceleration stops, the magnet valve is
held at position "2" to maintain brake fluid pressure .
17