1997 SUBARU LEGACY ignition

B4M0743
1. CHECK ENGINE TROUBLE CODE.
1) Read out engine trouble code.
2) Is trouble code 39 in memory?
B4M0395A
2. CHECK INPUT VOLTAGE OF ABS/TCS CONTROL
MODULE.
1) Turn ignition switch OFF.
2) Disconnect ABS/TCS control module connectors.
3) Turn ignition switch ON, while engine is idling.
4) Measure voltage between ABS/TCS control module
connector and body.
Connector & terminal / Specified voltage:
(P5) No. 1—body / 14.5±0.3 V
79
4-4bBRAKES
8. Diagnostics Chart with Trouble Code

B4M0733A
3. CHECK GROUND SHORT OF HARNESS.
1) Turn ignition switch OFF.
2) Remove No. 18 fuse from fuse and joint box.
3) Disconnect ABS/TCS control module connectors.
4) Measure resistance between ABS/TCS control module
connector and body.
Connector & terminal / Specified resistance:
(P5) No. 1—body/1MΩor more
B4M0405A
4. CHECK GROUND CIRCUIT OF ABS/TCS CONTROL
MODULE.
1) Turn ignition switch OFF.
2) Disconnect connector from ABS/TCS control module.
3) Measure resistance between ABS/TCS control module
connector and body.
Connector & terminal / Specified resistance:
(P4) No. 6—body / 1Ωor less
(P5) No. 5—body / 1Ωor less
(P7) No. 15—body / 1Ωor less
5. CHECK GENERATOR FUNCTION.
1) When the ignition key is at OFF, check the charge warn-
ing light is off.
2) Turn the key ON and ensure the light comes on.
3) Keep the engine running at idle and ensure the light
goes off.
B4M0473A
B4M0395A
6. CHECK INPUT VOLTAGE OF ABS/TCS CONTROL
MODULE.
1) Turn ignition switch OFF.
2) Disconnect ABS/TCS control module connectors.
3) Turn ignition switch ON.
4) Measure voltage between ABS/TCS control module
connector and body.
Connector & terminal / Specified voltage:
(P7) No. 20—body/2Vorless (Engine OFF)
(P7) No. 20—body / 10—14 V (Engine idling)
(P5) No. 1—body / 10—13 V (Engine OFF)
80
4-4bBRAKES
8. Diagnostics Chart with Trouble Code

B4M0742
B4M0734A
1. CHECK CONTACT POINT OF PRESSURE SWITCH.
1) Turn ignition switch OFF.
2) Disconnect hydraulic unit connector.
3) Measure resistance between hydraulic unit connector
terminals.
Connector & terminal / Specified resistance:
(F12) No. 1—No.2/1MΩor more (With brake
pedal
depressed)
(F12) No. 1—No.2/1Ωor less (Without brake
pedal depressed)
82
4-4bBRAKES
8. Diagnostics Chart with Trouble Code

B4M0735A
2. CHECK BODY SHORT OF PRESSURE SWITCH.
1) Turn ignition switch OFF.
2) Disconnect hydraulic unit connector.
3) Measure resistance between hydraulic unit connector
and body.
Connector & terminal / Specified resistance:
(F12) No. 1—body/1MΩor more
(F12) No. 2—body/1MΩor more
B4M0477A
3. CHECK HARNESS BETWEEN PRESSURE SWITCH
AND ABS/TCS CONTROL MODULE.
1) Turn ignition switch OFF.
2) Connect hydraulic unit connector.
3) Disconnect ABS/TCS control module connector.
4) Measure resistance between ABS/TCS control module
connector terminals.
Connector & terminal / Specified resistance:
(P7) No. 6—No.18/1MΩor more (With brake
pedal
depressed)
(P7) No. 6—No. 18 / 1Ωor less (Without brake
pedal depressed)
B4M0478A
4. CHECK BODY SHORT OF PRESSURE SWITCH
HARNESS.
1) Turn ignition switch OFF.
2) Disconnect ABS/TCS control module connector.
3) Measure resistance between ABS/TCS control module
connector and body.
Connector & terminal / Specified resistance:
(P7) No. 6—body/1MΩor more
(P7) No. 18—body/1MΩor more
B4M0466A
5. CHECK CONTACT POINT OF STOP LIGHT
SWITCH.
1) Turn ignition switch OFF.
2) Disconnect stop light switch connectors.
3) Remove stroke sensor.
4) Measure resistance between stroke sensor terminals.
83
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8. Diagnostics Chart with Trouble Code

Terminal:
No. 2—No. 3
Stroke
Unit: mm (in)Specified
resistance
0—2.2±1.0 (0—0.087±0.039) 1 MΩor more
2.2±1.0—18.0±0.5 (0.087±0.039—0.709±0.020) 1Ωor less
NOTE:
Stroke = 0 when the rod is completely drawn in.
B4M0467A
6. CHECK BODY SHORT OF STOP LIGHT SWITCH.
1) Turn ignition switch OFF.
2) Disconnect stroke sensor connectors.
3) Remove stroke sensor.
4) Measure resistance between stroke sensor terminal
and stroke sensor threads.
Terminal / Specified resistance:
No. 2—stroke sensor threads/1MΩor more
No. 3—stroke sensor threads/1MΩor more
B4M0468A
7. CHECK POWER SUPPLY OF STOP LIGHT
SWITCH.
1) Turn ignition switch OFF.
2) Disconnect stroke sensor connector.
3) Measure voltage between stroke sensor connector and
body.
Connector & terminal / Specified voltage:
(B67) No. 3—body / 10—13 V
B4M0469A
8. CHECK INPUT VOLTAGE OF ABS/TCS CONTROL
MODULE.
1) Turn ignition switch OFF.
2) Install stroke sensor.
3) Connect stroke sensor connector.
4) Disconnect ABS/TCS control module connector.
5) Measure voltage between ABS/TCS control module
connector and body.
Connector & terminal / Specified voltage:
(P7) No. 7—body / 10—13 V (With brake pedal
depressed)
(P7) No. 7—body/0V(Without brake pedal
depressed)
84
4-4bBRAKES
8. Diagnostics Chart with Trouble Code

B4M0479
B: MODE F00
—ROM ID NUMBER (ROM)—
CONDITION:
Ignition switch ON
SPECIFIED DATA:
Presentation display

Probable cause (Item outside“specified data”)
1. Error 1
Check for loose or disconnected connector, and
discontinued circuit, etc.
2. Error 2Check for poor contact of cartridge, or different type
cartridge.
B4M0480
C: MODE F01 AND F05
—FRONT RIGHT WHEEL SPEED SIGNAL
(FR)—

Compare speedometer with monitor indications.

F01: FR wheel speed is indicated in mile per hour (mile/
h).

F05: FR wheel speed is indicated in kilometer per hour
(km/h).
NOTE:
The monitor as shown, indicates that FR wheel speed is 30
mile/h.
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9. Select Monitor Function Mode

Contents Terminal No.Input/Output signal
Measured value and measuring conditions
ABS sensor
(Wheel
speed
sensor)Front left wheel 49—19
0.12—1V
(When it is 20 Hz.) Front right wheel 14—15
Rear left wheel 16—17
Rear right wheel 18—46
Hydraulic
control unitSolenoid
valveFront left outlet 51—1
10—13 V when the valve is OFF and
less than 1.5 V when the valve is ON. Front right outlet 3—1
Rear left outlet 4—1
Rear right outlet 50—1
Front left inlet 24—1
Front right inlet 30—1
Rear left inlet 31—1
Rear right inlet 23—1
Relay boxValve relay power supply 27—110—13 V when ignition switch is ON.
Valve relay coil 47—1 Less than 1.5 V when ignition switch is ON.
Motor relay coil 22—1More than 10 V when the ABS control does not operate still
and less than 1.5 V when ABS operates.
Motor monitoring 10—1Less than 1.5 V when the ABS control does not operate still
and more than 10 V when ABS operates.
G sensor
(AWD
model only)power supply 8—45 4.75—5.25 V
ground 45—
output 7—45 2.3±0.2 V when vehicle is in horizontal position.
Stop light switch 36—1Less than 1.5 V when the stop light is OFF and more than
4.5 V when the stop light is ON.
ABS warning light 54—1Less than 1.5 V during 1.5 seconds when ignition switch is
ON, and 10—14 V after 1.5 seconds.
AT ABS signal
(AT model only)12—1Less than 1.5 V when the ABS control does not operate still
and more than 5.5 V when ABS operates.
ABS operation signal monitor 39—1Less than 1.5 V when the ABS control does not operate still
and more than 5.5 V when ABS operates.
Select
monitorData is received. 11—1 Less than 1.5 V when no data is received.
Data is sent. 38—1 4.75—5.25 V when no data is sent.
Diagnosis
connectorTerminal No. 3 5—110—14 V when ignition switch is ON.
Terminal No. 6 13—110—14 V when ignition switch is ON.
Power supply 28—110—14 V when ignition switch is ON.
Grounding line 1—
Grounding line 55—
8
4-4cBRAKES [ABS 5.3 TYPE]
5. Control Module I/O Signal

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