check engine SUBARU LEGACY 1996 Service Repair Manual

12. Phenomena Peculiar to the System
1. WHEN TRAVELING WITH EXTREMELY UNDER
INFLATED TIRES
The TCS is apt to operate (particularly when turning) and,
when it operates, acceleration can become slow*. This
state is not abnormal. Immediately restore the tires to nor-
mal by traveling after releasing the TCS with the TCS OFF
switch.
* Poor acceleration is sometimes caused by the engine
itself. Check whether or not the TCS operating indicator
light (green) comes on to determine that the failure is
caused by the TCS control.
2. WHEN THE T TIRES ARE FITTED
The TCS is apt to operate (particularly when turning) and,
when it operates, acceleration can become slow. This state
is not abnormal. Immediately restore the tires to normal by
traveling after releasing the TCS with the TCS OFF switch.
3. WHEN OPERATING THE TCS CONTINUOUSLY ON
A SLOPE IMPOSSIBLE TO CLIMB OR IN STACK
S TAT E
When operating the TCS for a long time, it can be auto-
matically turned off (the OFF indicator light will come on),
stopping braking. This state is not abnormal. It automati-
cally resets by stopping and leaving the vehicle.
4. WHEN HEAVY LOAD IS PLACED ON THE BRAKES
If service brakes are used too often when descending a
long slope, heavy load can be placed on the brakes. To
prevent this problem, the TCS is automatically turned off
(the OFF indicator light will come on). This state is not
abnormal. Stop the vehicle and leave it in the same way as
step 3, it automatically resets.
5. KICKBACK TO THE BRAKE PEDAL WHEN THE
ABS IS OPERATING
Compared with ABS of the AWD model system, pedal kick-
back with large amplitude of vibration and long cycle can
be felt. This is caused by the difference in system configu-
ration and, therefore, not abnormal. If you receive an
inquiry from your clients, fully explain this point.
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12. Phenomena Peculiar to the System

6. INSPECTOR
Before advancing the vehicle after the engine starts, drive
the pump motor and valve for a very short time to function-
ally check the ABS/TCS brakes. It is not abnormal if, at this
time, operating noises of the valve and motor are produced
or kickback of the brake pedal is felt when stepping on the
pedal.
7. WHEN ATTACHING CHAINS
It is sometimes a good idea to turn off the TCS for better
advancing and accelerating the vehicle.
8. WHEN A DRUM TESTER IS USED (SPEEDOMETER
TEST, EXHAUST GAS TEST, BRAKE TEST, ETC.)
Before performing tests, turn the TCS off by operating the
TCS OFF switch or disconnect the fuse of ECM input
power source to put the machine out of operation. If oper-
ating other parts to put the TCS in the fail state
intentionally, trouble code will be recorded. Make sure to
clear the memory. Also, in a 2-wheel tester, wheel speed
sensor failure can be detected, making the TCS fail. This
case is also not abnormal and clearing the memory is
required.
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12. Phenomena Peculiar to the System

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
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4-4cBRAKES [ABS 5.3 TYPE]
6. Diagnostics Chart for On-board Diagnosis System

7. Diagnostics Chart for ABS Warning
Light Circuit and Diagnosis Circuit
Failure
A: ABS WARNING LIGHT DOES NOT COME
ON.
DIAGNOSIS:

ABS warning light circuit is open or shorted.
TROUBLE SYMPTOM:

When ignition switch is turned ON (engine OFF), ABS
warning light does not come on.
7A1.Check if other warning lights turn on.
7A2.Check ABS warning light bulb.
7A3.Check wiring harness.
7A4.Check battery short of relay box.
7A5.Check poor contact in connector between
combination meter and ABSCM.




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4-4cBRAKES [ABS 5.3 TYPE]
7. Diagnostics Chart for ABS Warning Light Circuit and Diagnosis Circuit Failure

WIRING DIAGRAM:
B4M1034
7A1CHECK IF OTHER WARNING LIGHTS
TURN ON.
Turn ignition switch to ON (engine OFF).
: Do other warning lights turn on?
: Go to step7A2.
: Repair combination meter.
15
4-4cBRAKES [ABS 5.3 TYPE]
7. Diagnostics Chart for ABS Warning Light Circuit and Diagnosis Circuit Failure

B: ABS WARNING LIGHT DOES NOT GO
OFF.
DIAGNOSIS:

ABS warning light circuit is open or shorted.
TROUBLE SYMPTOM:

When starting the engine and while ABS warning light is
kept ON.
7B1.Check installation of ABSCM connector.
7B2.Check generator.
7B3.Check battery terminal.
7B4.Check power supply of ABSCM.
7B5.Check ground circuit of ABSCM.
7B6.Check wiring harness.
7B7.Check relay box.
7B8.Check valve relay.
7B9.Check hydraulic control unit.
7B10.Check diagnosis terminal.
7B11.Check diagnosis line.
7B12.Check poor contact in ABSCM connector.











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4-4cBRAKES [ABS 5.3 TYPE]
7. Diagnostics Chart for ABS Warning Light Circuit and Diagnosis Circuit Failure

B4M0430
7B2
CHECK GENERATOR.
1) Start the engine.
2) Idle the engine.
3) Measure voltage between generator and chassis
ground.
: Terminal
Generator B terminal (+)—Chassis ground
():
Is voltage 10—15 V?
: Go to step7B3.
: Repair generator.
7B3
CHECK BATTERY TERMINAL.
Turn ignition switch to OFF.
: Is there poor contact at battery terminal?
: Repair battery terminal.
: Go to step7B4.
B4M0796A
7B4
CHECK POWER SUPPLY OF ABSCM.
1) Disconnect connector from ABSCM.
2) Start engine.
3) Idle the engine.
4) Measure voltage between ABSCM connector and chas-
sis ground.
: Connector & terminal
(F49) No. 28 (+)—Chassis ground ():
Is voltage 10—15 V?
: Go to step7B5.
: Repair ABSCM power supply circuit.
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4-4cBRAKES [ABS 5.3 TYPE]
7. Diagnostics Chart for ABS Warning Light Circuit and Diagnosis Circuit Failure

B4M0430
8H1
CHECK GENERATOR.
1) Start engine.
2) Idling after warm-up.
3) Measure voltage between generator B terminal and
chassis ground.
: Terminal
Generator B terminal—Chassis ground
Is voltage 10—15 V?
: Go to step8H2.
: Repair generator.
8H2
CHECK BATTERY TERMINAL.
Turn ignition switch to OFF.
: Are the positive and negative battery termi-
nals tightly clamped?
: Go to step8H3.
: Tighten the clamp of terminal.
B4M0842A
8H3
CHECK INPUT VOLTAGE OF ABSCM.
1) Disconnect connector from ABSCM.
2) Run the engine at idle.
3) Measure voltage between ABSCM connector and chas-
sis ground.
: Connector & terminal
(F49) No. 28 (+)—Chassis ground ()
Is voltage 10—15 V?
: Go to step8H4.
: Repair harness connector between battery, igni-
tion switch and ABSCM.
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4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

B4M0430
10C1
CHECK GENERATOR.
1) Start the engine.
2) Idle the engine.
3) Measure voltage between generator and chassis
ground.
: Terminal
Generator B terminal (+)—Chassis ground
():
Is voltage 10—15 V?
: Go to step10C2.
: Repair generator.
10C2
CHECK BATTERY TERMINAL.
Turn ignition switch to OFF.
: Is there poor contact at battery terminal?
: Repair battery terminal.
: Go to step10C3.
10C3CHECK COMMUNICATION OF SELECT
MONITOR.
Using the select monitor, check whether communication to
other system (such as engine, AT, etc.) can be executed
normally.
: Are the name and year of the system dis-
played on the select monitor?
: Go to step10C4.
: Repair select monitor communication cable and
connector.
10C4CHECK INSTALLATION OF ABSCM CON-
NECTOR.
Turn ignition switch to OFF.
: Is ABSCM connector inserted into ABSCM
until the clamp locks onto it?
: Go to step10C5.
: Insert ABSCM connector into ABSCM until the
clamp locks onto it.
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4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor

B4M0796A
10C5
CHECK POWER SUPPLY OF ABSCM.
1) Disconnect connector from ABSCM.
2) Start engine.
3) Idle the engine.
4) Measure voltage between ABSCM connector and chas-
sis ground.
: Connector & terminal
(F49) No. 28 (+)—Chassis ground ():
Is voltage 10—15 V?
: Go to step10C6.
: Repair ABSCM power supply circuit.
B4M0797A
10C6
CHECK GROUND CIRCUIT OF ABSCM.
1) Turn ignition switch to OFF.
2) Measure resistance between ABSCM connector and
chassis ground.
: Connector & terminal
(F49) No. 1—Chassis ground:
(F49) No. 55—Chassis ground:
Is resistance less than 0.5Ω?
: Repair harness/connector between ABSCM and
select monitor.
: Go to step10C7.
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4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor