Page 2873 of 3342
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.
268
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor
Page 2874 of 3342
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.
269
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor
Page 2875 of 3342

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 distanceHydraulic 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 draggingHydraulic unit (solenoid valve)
ABS sensor
Master cylinder
Brake (caliper & piston)
Parking brake
Axle & wheels
Brake pedal play
Long brake pedal strokeAir in brake line
Brake pedal play
Vehicle pitchingSuspension play or fatigue (reduced damping)
Incorrect wiring or piping connections
Road surface (uneven)
Unstable or uneven brakingHydraulic 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 vibrationIncorrect wiring or piping connections
Road surface (uneven)
Noise from hydraulic unitHydraulic unit (mount bushing)
ABS sensor
Brake piping
Noise from front of vehicleHydraulic 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 vehicleABS sensor
Brake (caliper & piston, pads, rotor)
Parking brake
Brake piping
Suspension play or fatigue
270
4-4cBRAKES [ABS 5.3 TYPE]
11. General Diagnostics Table
Page 2876 of 3342
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.
271
4-4cBRAKES [ABS 5.3 TYPE]
11. General Diagnostics Table
Page 2877 of 3342

1. Supplemental Restraint System
“Airbag”
Airbag system wiring harness is routed near the ABS
sensor, ABS control module and hydraulic control unit.
CAUTION:
All Airbag system wiring harness and connectors
are colored yellow. Do not use electrical test equip-
ment on these circuit.
Be careful not to damage Airbag system wiring har-
ness when servicing the ABS sensor, ABS control
module and hydraulic control unit.
2. Pre-inspection
Before performing diagnostics, check the following items
which might affect ABS problems:
A: MECHANICAL INSPECTION
1. POWER SUPPLY
1) Measure battery voltage and specific gravity of electro-
lyte.
Standard voltage: 12 V, or more
Specific gravity: Above 1.260
2) Check the condition of the main and other fuses, and
harnesses and connectors. Also check for proper ground-
ing.
2. BRAKE FLUID
1) Check brake fluid level.
2) Check brake fluid leakage.
3. BRAKE DRAG
Check brake drag.
4. BRAKE PAD AND ROTOR
Check brake pad and rotor.
5. TIRE SPECIFICATIONS, TIRE WEAR AND AIR
PRESSURE
Check tire specifications, tire wear and air pressure.
to 4-2 [S1A1], 4-2 [S1A2].>
2
4-4dBRAKES [ABS 5.3i TYPE]
1. Supplemental Restraint System“Airbag”- 2. Pre-inspection
Page 2878 of 3342

1. Supplemental Restraint System
“Airbag”
Airbag system wiring harness is routed near the ABS
sensor, ABS control module and hydraulic control unit.
CAUTION:
All Airbag system wiring harness and connectors
are colored yellow. Do not use electrical test equip-
ment on these circuit.
Be careful not to damage Airbag system wiring har-
ness when servicing the ABS sensor, ABS control
module and hydraulic control unit.
2. Pre-inspection
Before performing diagnostics, check the following items
which might affect ABS problems:
A: MECHANICAL INSPECTION
1. POWER SUPPLY
1) Measure battery voltage and specific gravity of electro-
lyte.
Standard voltage: 12 V, or more
Specific gravity: Above 1.260
2) Check the condition of the main and other fuses, and
harnesses and connectors. Also check for proper ground-
ing.
2. BRAKE FLUID
1) Check brake fluid level.
2) Check brake fluid leakage.
3. BRAKE DRAG
Check brake drag.
4. BRAKE PAD AND ROTOR
Check brake pad and rotor.
5. TIRE SPECIFICATIONS, TIRE WEAR AND AIR
PRESSURE
Check tire specifications, tire wear and air pressure.
to 4-2 [S1A1], 4-2 [S1A2].>
2
4-4dBRAKES [ABS 5.3i TYPE]
1. Supplemental Restraint System“Airbag”- 2. Pre-inspection
Page 2879 of 3342
B: ELECTRICAL INSPECTION
1. WARNING LIGHT ILLUMINATION PATTERN
B4M0781A
1) When the ABS warning light does not illuminate in
accordance with this illumination pattern, there must be an
electrical malfunction.
2) When the ABS warning light remains constantly OFF,
repair the ABS warning light circuit or diagnosis circuit.
NOTE:
Even though the ABS warning light does not go out 1.5
seconds after it illuminates, the ABS system operates nor-
mally when the warning light goes out while driving at
approximately 12 km/h (7 MPH). However, the Anti-lock
brakes do not work while the ABS warning light is illumi-
nated.
3
4-4dBRAKES [ABS 5.3i TYPE]
2. Pre-inspection
Page 2880 of 3342
3. Electrical Components Location
B4M1225A
1ABS control module and hydraulic control unit
(ABSCM&H/U)
2Proportioning valve
3Diagnosis connector
4ABS warning light
5Data link connector (for Subaru select monitor)
6Transmission control module (only AT vehicle)
7Tone wheel
8ABS sensor
9Wheel cylinder
10G sensor (only AWD vehicle)
11Brake switch
12Master cylinder
4
4-4dBRAKES [ABS 5.3i TYPE]
3. Electrical Components Location