Pulse signal

Parking brake switch

26

Pulse signal

Rear brake caliper RH

34

Pulse signal

Rear brake caliper RH

35

Pulse signal

Rear brake caliper LH

44

Pulse signal

Rear brake caliper LH

45

Pulse signal

Hill hold switch

6 — 46

10 — 15 V when the hill hold switch is ON.

Parking brake indicator light

3 — 46

0 V when the light is on; 10 — 15 V when the light is off

Brake fluid level switch

8 — 46

10 — 15 V when the ignition switch is ON.

Clutch stroke sensor power supply

11— 46

4.8— 5.2 V

Clutch stroke sensor ground

15

—

Clutch stroke sensor signal

15

Pulse signal

CAN communication line (H)

10

Pulse signal

CAN communication line (L)

13

Pulse signal

Ground

46

—

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8-24
Normal Voltage at EPB Motor in OFF Condition

Voltage to the two caliper wires is pulsed at the same polarity which allows for faster control.
The HCU can ground either wire while leaving the other at 12 volts positive to activate the EPB
motor.

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New EPB Features

The Sliding Prevention feature of the EPB allows for self activation of the EPB motor to increase
the tension to the brake pads, if the parking brake had been previously set. Sliding Prevention
is activated if the wheel speed sensors detect vehicle movement within 15 minutes of the EPB
activation.
The Temperature Compensation feature of the EPB functions by calculating brake component
temperature from information obtained by the CAN and HCU. The Ambient air temperature, vehicle
speed, road incline, service brake use frequency, and other vehicle information are considered
when calculating brake component temperature. Higher temperatures equate to expanded parts
which will contract as they cool. This could produce a situation where the initial EPB activation is
not strong enough to maintain vehicle position. Compensation for high temperature is achieved
by two methods;
1. The EPB is activated with the Engine operating or CAN still operating. All necessary data is
available to the EPB control unit (HCU) and the EPB motor applies additional mechanical
force to the brake pads.
2. The EPB is activated with the Engine off and the CAN in sleep mode. Data to determine
brake component temperature is not available to the EPB control unit (HCU). The initial EPB
activation will be limited to learned values. An additional application of the EPB motor will
be self activated by the EPB control unit (HCU) 2 minutes and 30 seconds after the EPB
was initially set. This will tighten any clearances that may have developed from contracting
brake parts.
An Automatic adjustment procedure is performed if no EPB operation is detected. The EPB control
unit (HCU) monitors the driving mileage and will self activate the EPB with the engine off once
every 1864 miles (3000 kilometers). This procedure repositions the ball nut clearance from the
back face of the hydraulic piston and tests the EPB motor drive circuits. The EPB will remain on
after the adjustment. EPB release is accomplished with the automatic release feature or manual
release while pressing the brake pedal.

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Emergency Brake Operation
The EPB also provides for an Emergency Brake function that can be activated while the vehicle
is in motion. Pulling up on the EPB control lever and holding the lever upward will activate the
Emergency Brake. The 2015 Legacy and Outback Emergency Brake will first attempt to slow down
through the use of the normal hydraulic components. The Motor Relay and Valve Relay in the HCU
will activate, supplying hydraulic pressure to all brake calipers (Front and Rear). Once maximum
braking is occurring (just before wheel lock up), the pump will turn off and hold mode of ABS will
maintain the current braking pressure. The EPB motor will activate only after the vehicle speed
drops below a set value.

8-25
Emergency Brake ON

If hydraulic pressure cannot be established, the EPB motor will activate immediately. The rear
wheels will lock up and unlock while the EPB switch is held in the on position. The EPB control
unit (HCU) will control the application and release of the EPB based on wheel speed sensor input
and always pulse the two sides together.
Emergency Release of the EPB
If the parking brake cannot be released with the EPB switch (example motor sticking), it is necessary
to remove the parking brake motor and actuator from the caliper body.
How to release
1. Lift the vehicle with a jack and remove the tire.
2. Remove the EPB connector from the motor.
3. Remove the motor attachment bolts (2 x 5 mm hexagon bolt), turn the piston shaft clockwise
to loosen the ball screw and confirm the release of the EPB.
4. Install the motor.
5. Install the tire and put the vehicle on the ground.
6. Release the EPB on the opposite side in the same way.
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Caution: If you loosen the motor attachment bolts with the parking brake engaged, the motor body
will rotate. Use caution to prevent pinching of fingers. Support and hold the actuator and
motor assembly in place and slowly allow it to move to a low tension position before
removing from the caliper.
Caution: If you release the parking brake, the vehicle can start moving. Therefore, check the slope
of the road and be sure the vehicle is securely stopped and front wheels are chocked.

Note:

While the motor is removed from the caliper, dust may contaminate the caliper.
Therefore, after releasing the parking brake, install the motor body and move
(drive) the vehicle.

The motor case contacts with
the caliper and stops.
(The motor case turns clockwise
when the bolts are loosened.)

The motor case contacts with
the caliper housing and stops.
(The motor case turns clockwise
when the bolts are loosened.)

8-26

8-27

Left Side

Right Side

Install the new actuator seal after the EPB has been restored.

8-28
Retracting Ball Nut

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Servicing Rear Brake Pads
Prepare the Subaru Select Monitor and SDI box and navigate to the Work Support of the ABS/
VDC menu. Follow the steps below to correctly park and reposition the ball nut during installation
of new brake pads.

8-29

8-30

Work Support

Note:

Brake Maintenance Mode

The EPB must be in the released position before removing rear brake pads.

1. Select “Brake Maintenance Mode” in the SSM III before replacement. (The EPB motor will
rotate in the release direction).
2. Warning: The EPB can be operated with the ignition off, be sure to follow the steps
below to place the EPB in a safe condition.
3. Turn the ignition switch to off. Remove the battery negative terminal or disconnect the EPB
motor harness connector from the EPB. Be sure to reconnect after all work is performed.
4. Push the hydraulic piston manually back into the caliper. Install the new brake pads.
5. After installation, restart the“Brake Maintenance Mode” and make the initial settings of the
EPB.
Note:

DTC “C1984” will be generated after selecting and completing “Brake
Maintenance Mode”. Clear the DTC before test driving the vehicle.

Note:

The Parking Brake Break In procedure has been eliminated and no Parking
Brake, Break In procedure is required on the new system.

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When the SSM III is not used (In shops that do not have the SSM III):
After removing the pad, turn the piston clockwise (release direction) with the piston rotating tool.

8-31
Turning in Ball Nut (Generic tool)

After installing the pad, operate the foot brake to move the piston to proper position. Operate the
EPB 5 times or more (with the parking brake switch) to move the ball screw to the proper position.
(It is prohibited to push the piston out with the EPB and not with the foot brake).

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NOTES:

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Electric Power Steering (EPS)
Introduction
An enhanced Electric Power Steering (EPS) system has been adopted for the 2015 Legacy and
Outback. This design is similar to 2012 Impreza and 2014 Forester models. In addition to a more
accurate and natural steering feel, the adoption of EPS provides a 2 percent improvement in fuel
efficiency over the current hydraulic system.

9-1
2015 Legacy and Outback Steering Rack

Major Changes
The EPS system on the 2015 Legacy and Outback features the following differences:
– The EPS Control Unit and Gear Box are now combined into a single assembly.
– The U, V, and W Motor Windings and the Resolver Sensor connections are provided
directly within the Control Unit.
– The Torque Sensor has been changed to a Flux Ring style sensor.

2015 Legacy/Outback

ECU

Impreza/Forester
ECU

9-2
EPS Comparison

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Electric Power Steering Circuit
Connections from the EPS Rack assembly to the vehicle have been reduced to two. Connector
B205 provides supply voltage and ground to the EPS while connector B203 contains CAN
communication and an Ignition Switch signal.

9-3
EPS Wiring Harness

FB-54
F/B FUSE NO. 10
(IG)

FB-42
F/B FUSE NO. 19
(IG)

MB-44
M/B FUSE NO. 17
(B)

DATA LINK
CONNECTOR

G

W

G/Y

REF. TO ENGINE ELECTRICAL
SYSTEM [1d] [2d] [3e] [4e]

G

8

W

16

B/L

5

B/Y

4

L

14

R

6

B40
POWER STEERING CM
B203
R
L
G/Y
W

2

B/R

1
B205

2
1
3

B204
R

A9

G

A10

P

A5

R

B1

B

B2

B206

TORQUE
SENSOR
1

R

A6

2

B

A7

3

G

A2

4

W

A1

B451

MOTOR

B/R

W

MB-33
SBF-2
(B)

A: B450
B: B452
GAP

9-4
EPS Wiring Diagram

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The EPS Control Unit and Gear Box are now combined into a single assembly. These components
cannot be serviced individually.

9-5
Control Unit Location

9-6

9-7

Control Unit Connections

Control Unit

Drive Motor
The EPS Motor is an eight pole Permanent Magnet Synchronous AC motor. DC power and ground
are supplied through connector B205 where it is controlled via “H” bridge transistors inside the
EPS Control Unit.

9-9

9-8
EPS Drive Motor (In Vehicle)

EPS Drive Motor

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9-11

Exposed Rotor Magnets

Drive Motor Coupling

Connections for the U, V, and W windings are supplied through a bus bar inside the control unit.

9-12

9-13

Drive Motor Windings

U, V, and W Connections

Resolver Sensor
The Resolver Sensor is mounted in the Motor Coupling housing and is press fitted to the motor
shaft. This Resolver uses a 5 tip Rotor where as Impreza and Forester models used a 4 tip Rotor.
Timing for the EPS motor is based on information provided by the Resolver Sensor.

9-15

9-14
Resolver Windings

Resolver 5 Tip Rotor

145