1997 SUBARU LEGACY light

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

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

4. Schematic
B4M1227A
1ABS control module and hydraulic control unit
(ABSCM&H/U)

2ABS control module area

3Valve relay

4Motor relay

5Motor

6Front left inlet solenoid valve

7Front left outlet solenoid valve

8Front right inlet solenoid valve

9Front right outlet solenoid valve

10Rear left inlet solenoid valve

11Rear left outlet solenoid valve

12Rear right inlet solenoid valve
13Rear right outlet solenoid valve

14Transmission control module (only AT model)

15Diagnosis connector

16Data link connector

17ABS warning light

18Stop light switch

19Stop light

20G sensor (only AWD model)

21Front left ABS sensor

22Front right ABS sensor

23Rear left ABS sensor

24Rear right ABS sensor
6
4-4dBRAKES [ABS 5.3i TYPE]
4. Schematic

5. Control Module I/O Signal
1. I/O SIGNAL VOLTAGE
B4M1228A
NOTE:

The terminal numbers in the ABS control module and
hydraulic control unit connector are as shown in the figure.

When the connector is removed from the ABSCM&H/U,
the connector switch closes the circuit between terminal
No. 21 and No. 23. The ABS warning light illuminates.
7
4-4dBRAKES [ABS 5.3i TYPE]
5. Control Module I/O Signal

ContentsTerminal No.
(+)—()Input/Output signal
Measured value and measuring conditions
ABS
sensor*2
(Wheel
speed
sensor)Front left wheel 9—10
0.12 — 1 V
(When it is 20 Hz.) Front right wheel 11—12
Rear left wheel 7—8
Rear right wheel 14—15
Valve relay power supply 24—23 10 — 15 V when ignition switch is ON.
Motor relay power supply 25—23 10 — 15 V when ignition switch is ON.
G sensor*2
(AWD
model only)power supply 30—28 4.75 — 5.25 V
ground 28 —
output 6—28 2.3±0.2 V when vehicle is in horizontal position.
Stop light switch*1 2—23Less than 1.5 V when the stop light is OFF and, 10 — 15 V
when the stop light is ON.
ABS warning light*2 21—23Less than 1.5 V during 1.5 seconds when ignition switch is
ON, and 10 — 15 V after 1.5 seconds.
AT ABS signal*2
(AT model only)31—23Less 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*2 3—23Less than 1.5 V when the ABS control does not operate still
and more than 5.5 V when ABS operates.
Select
monitor*2Data is received. 20—23 Less than 1.5 V when no data is received.
Data is sent. 5—23 4.75 — 5.25 V when no data is sent.
ABS
diagnosis
connector*2Terminal No. 3 29—23 10 — 15 V when ignition switch is ON.
Terminal No. 6 4—23 10 — 15 V when ignition switch is ON.
Power supply*1 1—23 10 — 15 V when ignition switch is ON.
Grounding line 23 —
Grounding line 26 —
*1: Measure the I/O signal voltage after removing the connector from the ABSCM&H/U terminal.
*2: Measure the I/O signal voltage at connector (F2) or (F1).
8
4-4dBRAKES [ABS 5.3i TYPE]
5. Control Module I/O Signal

When ABS warning light illuminates, read and record
trouble code indicated by ABS warning light.
B: CHECK LIST FOR INTERVIEW
Check the following items about the vehicle’s state.
1. THE STATE OF THE ABS WARNING LIGHT
ABS warning light
comes on.Always
Sometimes
Only once
Does not come on

When /how long does it come on?:
Ignition key positionLOCK
ACC
ON (before starting engine)
START
On after starting (Engine is running)
On after starting (Engine is stop)
TimingImmediately after ignition is ON.
Immediately after ignition starts.
When advancing km/h to km/h
MPH to MPH
While traveling at a constant speed km/h MPH
When decelerating km/h to km/h
MPH to MPH
When turning to right Steering angle : deg
Steering time : sec
When turning to left Steering angle : deg
Steering time : sec
When moving other electrical parts

Parts name :

Operating condition :
2. SYMPTOMS
ABS operating
conditionPerforms no work.
Operates only when abruptly applying brakes. Vehicle speed : km/h
MPH

How to step on brake pedal :
a) Operating time :sec
b) Operating noise :Produce /Does not produce

What kind of noise?Knock
Gong gong
Bong
Buzz
Gong gong buzz
Others :
c) Reaction force of brake pedal
Stick
Press down once with a clunk
Press and released
Others :
11
4-4dBRAKES [ABS 5.3i TYPE]
6. Diagnostics Chart for On-board Diagnosis System

C: INSPECTION MODE
Reproduce the condition under which the problem has
occurred as much as possible.
Drive the vehicle at a speed more than 40 km/h (25 MPH)
for at least one minute.
B4M0082D
D: TROUBLE CODES
When on-board diagnosis of the ABS control module
detects a problem, the information (up to a maximum of
three) will be stored in the EEP ROM as a trouble code.
When there are more than three, the most recent three will
be stored. (Stored codes will stay in memory until they are
cleared.)
1. CALLING UP A TROUBLE CODE
1) Take out diagnosis connector from side of driver’s seat
heater unit.
2) Turn ignition switch OFF.
3) Connect diagnosis connector terminal 6 to diagnosis
terminal.
4) Turn ignition switch ON.
5) ABS warning light is set in the diagnostic mode and
blinks to identify trouble code.
6) After the start code (11) is shown, the trouble codes will
be shown in order of the last information first.
These repeat for a maximum of 5 minutes.
NOTE:
When there are no trouble codes in memory, only the start
code (11) is shown.
B4M0232A
14
4-4dBRAKES [ABS 5.3i 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.
WIRING DIAGRAM:
B4M1230
16
4-4dBRAKES [ABS 5.3i TYPE]
7. Diagnostics Chart for ABS Warning Light Circuit and Diagnosis Circuit Failure