1996 SUBARU LEGACY Brakes

WIRING DIAGRAM:
B4M1050
10AK1CHECK ALL FOUR WHEELS FOR FREE
TURNING.
: Have the wheels been turned freely such as
when the vehicle is lifted up, or operated on
a rolling road?
: The ABS is normal. Erase the trouble code.
: Go to step10AK2.
B4M0927
10AK2CHECK OUTPUT OF G SENSOR USING
SELECT MONITOR.
1) Press F,1and 0on the select monitor.
2) Read the select monitor display.
: Is the indicated reading 2.3±0.2 V when the
vehicle is in horizontal position?
: Go to next step.
: Go to step10AK5.
267
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor

3) Remove console box.
4) Remove G sensor from vehicle. (Do not disconnect
connector.)
B4M0917A
5) Read the select monitor display.
: Is the indicated reading 3.9±0.2 V when G
sensor is inclined forwards to 90°?
: Go to next.
: Replace G sensor.
B4M0918A
: Is the indicated reading 0.7±0.2 V when G
sensor is inclined backwards to 90°?
: Go to step10AK3.
: Replace G sensor.
10AK3CHECK POOR CONTACT IN CONNEC-
TOR BETWEEN ABSCM AND G SENSOR.
: Is there poor contact in connector between
ABSCM and G sensor?
: Repair connector.
: Go to step10AK4.
268
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor

10AK4
CHECK ABSCM.
1) Connect all connectors.
2) Erase the memory.
3) Perform inspection mode.
4) Read out the trouble code.
: Is the same trouble code as in the current
diagnosis still being output?
: Replace ABSCM.
: Go to next.
: Are other trouble codes being output?
: Proceed with the diagnosis corresponding to the
trouble code.
: A temporary poor contact.
B4M0912A
10AK5CHECK BROKEN WIRE IN G SENSOR
OUTPUT HARNESS AND GROUND HAR-
NESS.
1) Turn ignition switch to OFF.
2) Disconnect connector from ABSCM.
3) Measure resistance between ABSCM connector termi-
nals.
: Connector & terminal
(F49) No. 7—No. 45
Is resistance 4.6±0.3 kΩ?
: Go to step10AK6.
: Repair harness between G sensor and ABSCM.
269
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor

B4M0915
10AK6
CHECK G SENSOR.
1) Remove console box.
2) Remove G sensor from vehicle.
3) Connect connector to G sensor.
4) Connect connector to ABSCM.
5) Turn ignition switch to ON.
6) Measure voltage between G sensor connector termi-
nals.
: Connector & terminal
(P11) No. 2 (+)—No.1()
Is voltage 2.3±0.2 V when G sensor is hori-
zontal?
: Go to next.
: Replace G sensor.
B4M0917A
: Connector & terminal
(P11) No. 2 (+)—No.1()
Is voltage 3.9±0.2 V when G sensor is
inclined forwards to 90°?
: Go to next.
: Replace G sensor.
B4M0918A
: Connector & terminal
(P11) No. 2 (+)—No.1()
Is voltage 0.7±0.2 V when G sensor is
inclined backwards to 90°?
: Go to step10AK7.
: Replace G sensor.
270
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor

10AK7
CHECK ABSCM.
1) Connect all connectors.
2) Erase the memory.
3) Perform inspection mode.
4) Read out the trouble code.
: Is the same trouble code as in the current
diagnosis still being output?
: Replace ABSCM.
: Go to next.
: Are other trouble codes being output?
: Proceed with the diagnosis corresponding to the
trouble code.
: A temporary poor contact.
271
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor

11. General Diagnostics Table
A: SYMPTOMS AND PROBABLE CAUSES
Symptom Probable faulty units/parts
Vehicle instability during brakingVehicle pulls to either side.
Hydraulic unit (solenoid valve)

ABS sensor

Brake (caliper & piston, pads)

Wheel alignment

Tire specifications, tire wear and air pressures

Incorrect wiring or piping connections

Road surface (uneven, camber)
Vehicle spins.
Hydraulic unit (solenoid valve)

ABS sensor

Brake (pads)

Tire specifications, tire wear and air pressures

Incorrect wiring or piping connections
Poor brakingLong braking/stopping distance
Hydraulic unit (solenoid valve)

Brake (pads)

Air in brake line

Tire specifications, tire wear and air pressures

Incorrect wiring or piping connections
Wheel locks.
Hydraulic unit (solenoid valve, motor)

ABS sensor

Incorrect wiring or piping connections
Brake dragging
Hydraulic unit (solenoid valve)

ABS sensor

Master cylinder

Brake (caliper & piston)

Parking brake

Axle & wheels

Brake pedal play
Long brake pedal stroke
Air in brake line

Brake pedal play
Vehicle pitching
Suspension play or fatigue (reduced damping)

Incorrect wiring or piping connections

Road surface (uneven)
Unstable or uneven braking
Hydraulic unit (solenoid valve)

ABS sensor

Brake (caliper & piston, pads)

Tire specifications, tire wear and air pressures

Incorrect wiring or piping connections

Road surface (uneven)
Vibration and/or noise (while
driving on slippery roads)Excessive pedal vibration
Incorrect wiring or piping connections

Road surface (uneven)
Noise from hydraulic unit
Hydraulic unit (mount bushing)

ABS sensor

Brake piping
Noise from front of vehicle
Hydraulic unit (mount bushing)

ABS sensor

Master cylinder

Brake (caliper & piston, pads, rotor)

Brake piping

Brake booster & check valve

Suspension play or fatigue
Noise from rear of vehicle
ABS sensor

Brake (caliper & piston, pads, rotor)

Parking brake

Brake piping

Suspension play or fatigue
272
4-4cBRAKES [ABS 5.3 TYPE]
11. General Diagnostics Table

B: CHECKING THE HYDRAULIC UNIT
OPERATION

1) Do ABS sequence control patterns take place in correct
order?
If not, check wiring and piping for incorrect connections.
2) Are oil pressure or braking force variations within speci-
fications?
If not, check master cylinder, brake piping, hydraulic unit,
proportioning valve and wheel cylinder for improper opera-
tion.
3) Does pedal hardness change before and after ABS
sequence control?
If so, bleed air from brake line.
273
4-4cBRAKES [ABS 5.3 TYPE]
11. General Diagnostics Table