Subaru Legacy 2015 - EPB Electrical Operation and Control

132
June 2014
2015 Legacy and Outback New Technology Training (Module 926)
EPB Electrical Operation and Control
The operation of the EPB at each rear brake caliper is accomplished using two wires that operate
the bidirectional movement of the EPB motors. There are no sensors incorporated into the caliper.
Sensing for apply and release is determined by the amount of amperage measured in the Hydraulic
Control Unit.
MB-8
SBF-15
(B)
VDC CM
B310
i156
i163
R153
GR
C15 W/G
P
W/R
R/Y
Y
5Y 35 Y/G 34 Y/B
R154
44 Y/L
45 Y
Y/G
Y/B
Y/L
Y
W
R
Y
L
6G
W/V
33 W/R 16 R/Y 8BR/Y
G
21 LG/R 46 B
B B
26 P/G 20 Y/W 19 3
B/G
LG
P Y
B
W/G
4
1
G
2R
1W
2R
1W
B16
1
2
BR/Y
P
7GR
12 W/G
2B
1Y
6P
5LG
B60
i112
27
28 26 25
B60
i112
1 2 3 4
i128
R40
2 3 5 6
R36
R140
R35
R149
1 2 1 2
23
24
GV
5
B479
J/C
:C291i
C15 W/G
W/G
i87C:
*
2
*
1
*
3
MB-7
M/B FUSE NO. 33
(B)
FB-52
F/B FUSE NO. 10
(IG)
FB-71
F/B FUSE NO. 14
(B)
EPB ON
EPB CONTROL SWITCH
HILL HOLD
SWITCH
BRAKE FLUID
LEVEL SWITCH
REF. TO GND [k]
FB-45
F/B FUSE NO. 3
(IG)
REAR BRAKE
CALIPER LH
REAR BRAKE
CALIPER RH
LOCK RELEASE
AUDIO
EPB Wiring Schematic
During apply control, the polarity of the wires is controlled to turn the ball nut counter clockwise.
This will screw the ball nut into the piston and place mechanical force on the inner brake pad
and pull the caliper inward to force the outer brake pad into the rotor. An initial current spike will
occur as the motor first starts to turn and then level off as the motor turns without opposing any
mechanical force. As the Hydraulic piston makes contact with the inner brake pad, current starts
to increase and continues to increase as the brake caliper is pulled inward. The amperage will
reach maximum level after both brake pads are contacting the rotor with a predetermined amount
of mechanical force.
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