1997 SUBARU LEGACY sensor

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

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

8. Diagnostics Chart with Trouble Code
by ABS Warning Light
A: LIST OF TROUBLE CODE
Trouble code Contents of diagnosis Ref. to
11Start code

Trouble code is shown after start code.

Only start code is shown in normal condition.—
21
Abnormal ABS sensor
(Open circuit or input voltage too high)Front right ABS sensor 4-4d [T8B0]
23 Front left ABS sensor 4-4d [T8C0]
25 Rear right ABS sensor 4-4d [T8D0]
27 Rear left ABS sensor 4-4d [T8E0]
22
Abnormal ABS sensor
(Abnormal ABS sensor signal)Front right ABS sensor 4-4d [T8F0]
24 Front left ABS sensor 4-4d [T8G0]
26 Rear right ABS sensor 4-4d [T8H0]
28 Rear left ABS sensor 4-4d [T8I0]
29 Any one of four 4-4d [T8J0]
31
Abnormal solenoid valve circuit(s) in ABS
control module and hydraulic unitFront right inlet valve 4-4d [T8K0]
32 Front right outlet valve 4-4d [T8O0]
33 Front left inlet valve 4-4d [T8L0]
34 Front left outlet valve 4-4d [T8P0]
35 Rear right inlet valve 4-4d [T8M0]
36 Rear right outlet valve 4-4d [T8Q0]
37 Rear left inlet valve 4-4d [T8N0]
38 Rear left outlet valve 4-4d [T8R0]
41 Abnormal ABS control module 4-4d [T8S0]
42 Source voltage is abnormal. 4-4d [T8T0]
44 A combination of AT control abnormal 4-4d [T8U0]
51 Abnormal valve relay4-4d [T8V0]
52 Abnormal motor and/or motor relay 4-4d [T8W0]
54 Abnormal stop light switch 4-4d [T8X0]
56 Abnormal G sensor output voltage 4-4d [T8Y0]
27
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light

B: TROUBLE CODE 21 (FRONT RH)
C: TROUBLE CODE 23 (FRONT LH)
D: TROUBLE CODE 25 (REAR RH)
E: TROUBLE CODE 27 (REAR LH)
—ABNORMAL ABS SENSOR (OPEN CIRCUIT
OR INPUT VOLTAGE TOO HIGH)—
DIAGNOSIS:

Faulty ABS sensor (Broken wire, input voltage too high)

Faulty harness connector
TROUBLE SYMPTOM:

ABS does not operate.
WIRING DIAGRAM:
B4M1238
28
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light

B4M0806E
B4M1036C
8E1
CHECK ABS SENSOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from ABS sensor.
3) Measure resistance of ABS sensor connector terminals.
Terminal
Front RH No. 1—No. 2:
Front LH No. 1—No. 2:
Rear RH No. 1—No. 2:
Rear LH No. 1—No. 2:
: Is the resistance between 0.8 and 1.2 kΩ?
: Go to step8E2.
: Replace ABS sensor.
B4M0807E
B4M1037C
8E2CHECK BATTERY SHORT OF ABS SEN-
SOR.
1) Disconnect connector from ABSCM&H/U.
2) Measure voltage between ABS sensor and chassis
ground.
Terminal
Front RH No. 1 (+)—Chassis ground ():
Front LH No. 1 (+)—Chassis ground ():
Rear RH No. 1 (+)—Chassis ground ():
Rear LH No. 1 (+)—Chassis ground ():
: Is the voltage less than 1 V?
: Go to step8E3.
: Replace ABS sensor.
29
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light

B4M0807E
B4M1037C
8E3CHECK BATTERY SHORT OF ABS SEN-
SOR.
1) Turn ignition switch to ON.
2) Measure voltage between ABS sensor and chassis
ground.
Terminal
Front RH No. 1 (+)—Chassis ground ():
Front LH No. 1 (+)—Chassis ground ():
Rear RH No. 1 (+)—Chassis ground ():
Rear LH No. 1 (+)—Chassis ground ():
: Is the voltage less than 1 V?
: Go to step8E4.
: Replace ABS sensor.
B4M1239A
8E4CHECK HARNESS/CONNECTOR
BETWEEN ABSCM&H/U AND ABS SEN-
SOR.
1) Turn ignition switch to OFF.
2) Connect connector to ABS sensor.
3) Measure resistance between ABSCM&H/U connector
terminals.
Connector & terminal
Trouble code 21 / (F49) No. 11—No. 12:
Trouble code 23 / (F49) No. 9—No. 10:
Trouble code 25 / (F49) No. 14—No. 15:
Trouble code 27 / (F49) No. 7—No. 8:
: Is the resistance between 0.8 and 1.2 kΩ?
: Go to step8E5.
: Repair harness/connector between ABSCM&H/U
and ABS sensor.
30
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light

B4M1240A
8E5
CHECK BATTERY SHORT OF HARNESS.
Measure voltage between ABSCM&H/U connector and
chassis ground.
Connector & terminal
Trouble code 21 / (F49) No. 11 (+)—Chassis ground
():
Trouble code 23 / (F49) No. 9 (+)—Chassis ground
():
Trouble code 25 / (F49) No. 14 (+)—Chassis ground
():
Trouble code 27 / (F49) No. 7 (+)—Chassis ground
():
: Is the voltage less than 1 V?
: Go to step8E6.
: Repair harness between ABSCM&H/U and ABS
sensor.
B4M1240A
8E6
CHECK BATTERY SHORT OF HARNESS.
1) Turn ignition switch to ON.
2) Measure voltage between ABSCM&H/U connector and
chassis ground.
Connector & terminal
Trouble code 21 / (F49) No. 11 (+)—Chassis ground
():
Trouble code 23 / (F49) No. 9 (+)—Chassis ground
():
Trouble code 25 / (F49) No. 14 (+)—Chassis ground
():
Trouble code 27 / (F49) No. 7 (+)—Chassis ground
():
: Is the voltage less than 1 V?
: Go to step8E7.
: Repair harness between ABSCM&H/U and ABS
sensor.
8E7CHECK INSTALLATION OF ABS SEN-
SOR.
Tightening torque:
32±10 N⋅m (3.3±1.0 kg-m, 24±7 ft-lb)
: Are the ABS sensor installation bolts tight-
ened securely?
: Go to step8E8.
: Tighten ABS sensor installation bolts securely.
31
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light