1996 SUBARU LEGACY air condition

11. General Diagnostics Table
: Primary expected causes: Secondary expected causes
Trouble conditions
SymptomsHydraulic
unit
Speed sensor
P valve
Master cylinder
Calipers and piston
Pad
Rotor
Hand brake
Piping
Mixture of air
Brake booster and check valve
Axle and wheel
Alignment
Play of pedal
Rough road surface
Semicylindrical road surface
Loose or worn suspension
Tire
Wrong connection and wiring
Stroke sensor Solenoid valve
Motor
Mount bush ABS function
Directional stability cannot be
obtained when braking.Vehicle turns to right or left. 
Vehicle spins.
Out-of-order brakesLong braking distance
 
Brakes lock.  
Brakes drag.
Long pedal stroke  
Abnormal vehicle pitching 
Unstable braking force. One-
side brake refuses to work. 
TCS function
When accelerating abruptly,
directional stability cannot be
obtained when traveling on a
slippery road surface.Vehicle moves unsteadily.
Handle refuses to work.
Handle loses control. 
Bad acceleration, engine stall-
ing (In addition to the causes
listed here, check the ECM
specifications.)Engine stalls. Engine speed
fails to increase.
Engine speed increases sud-
denly.
Vibration occurs and abnormal
noise is produced.

When applying brakes abruptly.

When accelerating abruptly.

When driving on a slippery
road surface.Brake pedal heavily vibrates
when applying brakes.
   
Loud hydraulic unit operating
noise
Noise is produced from front
of vehicle.
Noise is produced from rear of
vehicle.
NOTE:
This list includes no engine failure and transmission failure.
127
4-4bBRAKES
11. General Diagnostics Table

1. Supplemental Restraint System
“Airbag”
Airbag system wiring harness is routed near the ABS con-
trol module, ABS sensor 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 control module, ABS
sensor 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 [S1A2].>
2
4-4cBRAKES [ABS 5.3 TYPE]
1. Supplemental Restraint System“Airbag”- 2. Pre-inspection

1. Supplemental Restraint System
“Airbag”
Airbag system wiring harness is routed near the ABS con-
trol module, ABS sensor 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 control module, ABS
sensor 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 [S1A2].>
2
4-4cBRAKES [ABS 5.3 TYPE]
1. Supplemental Restraint System“Airbag”- 2. Pre-inspection

B: CHECK LIST FOR INTERVIEW
Check the following items about the vehicle’s state.
1. THE STATE OF THE WARNING LIGHTS
a. ABS warning light

1Is always on.2Sometimes comes on.3Comes on only once.4Does not come on.
When/how long does it come on?
Ignition key
position
1Lock2Acc3On (before starting engine)4Start5On after starting (Engine: run)

6On after starting (Engine: stop)
Timing
1Immediately after ignition is on.2Immediately after ignition starts.

3When advancing (Speedmiles/h,miles/h)4While traveling at a constant speed (Speedmiles/h)

5When decelerating (Speedmiles/h,miles/h)

6When turning (To right, to left, steering angledeg., steering timesec)

7When moving other electrical parts (Part name:, Operating condition)
2. SYMPTOMS
ABS operating
condition1Performs no work.2Operates only when abruptly applying brakes. (Conditions: vehicle speedmiles/h, how
to step on brake pedal
)

3Operating time (sec., etc.)4Operating noise (Produced/Not produced)

5What kind of noise? (Knock, gong gong, bong, buzz, gong gong buzz, etc.)

6Reaction force of brake pedal (Stick, pressed down once with a clunk, pressed and released, etc.)
Behavior of
vehicle
1Directional stability cannot be obtained or steering arm refuses to work when applying brakes (vehicle turns to
right, turns to left, spins, etc.
).

2Directional stability cannot be obtained or steering arm refuses to work when accelerating (vehicle turns to right,
turns to left, spins, etc.
).

3Brakes are out of order (braking distance is long, brakes lock or drag, pedal stroke is long, pedal sticks, etc.
).

4Poor acceleration (fails to accelerate, engine stalls, etc.).

5Vibration, abnormal noise (operating noise is loud, noise is produced during operation from the front of vehicle
(right, left) (tones:
), noise is produced during operation from the rear of vehicle (tones:, others
)

6Other phenomena (concrete symptoms)
3. CONDITIONS UNDER WHICH TROUBLE OCCURS
Environment1Weather (fine, cloudy, rain, snow, etc.)

2Ambient temperature (°C/°F)

3Road (urban area, suburbs, highway, general road, ascending slope, descending slope, paved road, gravel road,
muddy road, sandy place, etc.
)

4Road surface (dry, wet, new-fallen snow, compressed snow, frozen slope, etc.)
Conditions
1Brakes (decelerationg, continuous/intermittent)2Accelerator (accelerationg, continuous/intermittent)

3Travel speed (miles, advancing, accelerating, reducing speed, low speed, turning, etc.)

4Condition of tire of each wheel (air pressure, degree of wear, whether or not genuine parts are used,
whether or not chain is passed around tires, whether or not T tire is used.) others (
)

5Condition of suspension alignment ()

6Loading state ()
4. REPAIRED PARTS ARE USED OR NOT
11
4-4cBRAKES [ABS 5.3 TYPE]
6. Diagnostics Chart for On-board Diagnosis System

B5M0115B
B: ON-BOARD DIAGNOSTIC
When the airbag system is in functioning condition, the
airbag warning light will remain on for 8 seconds and go out
when the ignition switch is set to ON.
If there is any malfunction, the airbag warning light will
either stay on or off continuously. In such cases, perform
on-board diagnostic in accordance with the specified pro-
cedure to determine trouble codes.
1) Turn ignition switch ON (with engine OFF).
2) Connect DIAG. terminal

1to No. 1 terminal of diagno-
sis connector

2located below lower cover.
3) Check in accordance with the trouble code indicated by
the AIRBAG warning light, and record the trouble codes.
4) Turn the ignition switch “OFF” and remove the DIAG.
terminal from No.1 terminal of diagnosis connector.
B5M0116B
C: CLEAR MEMORY
After eliminating problem as per trouble code, clear
memory as follows:
Make sure ignition switch is ON (and engine off). Connect
one DIAG. terminal

1on diagnosis connector
2terminal
No. 1.
While warning light is flashing, connect the other DIAG.
terminal

3on terminal No. 2 for at least three seconds.
After memory is cleared, normal warning light flashing rate
resumes. (Warning light flashes every 0.6 seconds ON-
OFF operation.) Memory cannot be cleared if any problem
exists.
After clear memory and then DIAG. terminals

1and
3,
extract from diagnosis connector

2.
9
5-5SUPPLEMENTAL RESTRAINT SYSTEM
4. Diagnostics Chart for On-board Diagnostic System

B5M0115B
B: ON-BOARD DIAGNOSTIC
When the airbag system is in functioning condition, the
airbag warning light will remain on for 8 seconds and go out
when the ignition switch is set to ON.
If there is any malfunction, the airbag warning light will
either stay on or off continuously. In such cases, perform
on-board diagnostic in accordance with the specified pro-
cedure to determine trouble codes.
1) Turn ignition switch ON (with engine OFF).
2) Connect DIAG. terminal

1to No. 1 terminal of diagno-
sis connector

2located below lower cover.
3) Check in accordance with the trouble code indicated by
the AIRBAG warning light, and record the trouble codes.
4) Turn the ignition switch“OFF”and remove the DIAG.
terminal from No. 1 terminal of diagnosis connector.
B5M0116B
C: CLEAR MEMORY
After eliminating problem as per trouble code, clear
memory as follows:
Make sure ignition switch is ON (and engine off). Connect
one DIAG. terminal

1on diagnosis connector
2terminal
No. 1.
While warning light is flashing, connect the other DIAG.
terminal

3on terminal No. 2 for at least three seconds.
After memory is cleared, normal warning light flashing rate
resumes. (Warning light flashes every 0.6 seconds ON-
OFF operation.) Memory cannot be cleared if any problem
exists.
After clear memory and then DIAG. terminals

1and
3,
extract from diagnosis connector

2.
10
5-5bSUPPLEMENTAL RESTRAINT SYSTEM (ELECTRIC SENSOR TYPE)
4. Diagnostics Chart for On-board Diagnostic System

5. Control Module I/O Signal
G6M0015
ContentTerminal
No.Measuring conditions and I/O signals (ignition switch ON and engine idling)
Main power supply 2
Battery voltage is present when main power is turned ON.

“0”volt is present when main power is turned OFF.
Inhibitor switch (AT) (U.S.A.)
N position switch (AT) (CANADA)4
“0”volt is present when selector lever is set to P or N position (CANADA: N position only).

Battery voltage is present when selector lever is other than P or N position (CANADA: N
position only).
Air valve 5
“0”volt is present when vehicle is stopped.

ON-and-OFF (“0”-and-battery voltage) operation is alternately repeated while cruise control
is operating.
GND 6—
Vacuum pump motor 7
“0”volt is present when vehicle is stopped.

ON-and-OFF (“0”-and-battery voltage) operation is alternately repeated while cruise control
is operating.
Data link connector 8—
RESUME/ACCEL switch 9
Battery voltage is present when switch is turned ON.

“0”volt is present when switch is turned OFF.
SET/COAST switch 10
Battery voltage is present when switch is turned ON.

“0”volt is present when switch is turned OFF.
Ignition switch 12
Battery voltage is present when ignition switch is turned ON.

“0”volt is present when ignition switch is turned OFF.
Release valve 13
“0”volt is present when vehicle is stopped.

ON-and-OFF (“0”-and-battery voltage) operation is alternately repeated while cruise control
is operating.
Power supply to vacuum pump
motor, air valve, release valve14
“0”volt is present when vehicle is stopped.

Battery voltage is present while cruise control is operating.
Cruise main switch 15
Battery voltage is present during pressing the main switch, and then approx. 12 V is
present while switch is turned ON.

“0”volt is present when switch is turned OFF.
Brake switch 16Turn the cruise main switch to ON and leave clutch pedal released (MT).
Then check that;

“0”volt is present when brake pedal is depressed.

Battery voltage is present when brake pedal is released.
Additionally only in MT vehicle, keep the cruise main switch to ON and leave brake pedal
released.
Then check that;

“0”volt is present when clutch pedal is depressed.

Battery voltage is present when clutch pedal is released.
Data link connector 17—
Data link connector 18—
Vehicle speed sensor 2 19Lift-up the vehicle until all four wheels are raised off ground, and then rotate any wheel manu-
ally.
Approx. 5 and 0 volt pulse signals are alternately input to cruise control module.
Stop light switch 20Turn ignition switch to OFF.
Then check that;

Battery voltage is present when brake pedal is depressed.

“0”volt is present when brake pedal is released.
NOTE:
Voltage at terminals 5, 7, 13 and 14 cannot be checked unless vehicle is driving by cruise control operation.
7
6-2BODY ELECTRICAL SYSTEM
5. Control Module I/O Signal

C: CHECK CRUISE CONTROL MAIN SWITCH
DIAGNOSIS:

Faulty cruise control main switch, or open harness.
TROUBLE SYMPTOM:

Cruise control main switch is not turned ON and cruise
control cannot be set.
NOTE:
When the main relay (built-in cruise control module)
operates, the main switch circuit is in normal condition.
The main relay operation can be checked by hearing the
operation sounds.
This operation sounds will be heard when ignition switch
and cruise control main switch is turned to ON.
1. Check fuse and power supply.
OK
Not OK
Melted fuse,repair the shorted part of the circuit.
,replace fuse.
2. Check cruise control main switch.
OK
Not OK
Open harness,repair faulty main switch.,
replace.
3. Check harness connector between cruise
control main switch and cruise control
module.
OK
Not OK
Repair or replace wiring harness.
Failure of the cruise control module.
B6M0275



14
6-2BODY ELECTRICAL SYSTEM
7. Diagnostics Chart for Power Line