SUBARU LEGACY 1997 Service Repair Manual

C: TROUBLE CODE DOES NOT APPEAR.
DIAGNOSIS:

Diagnosis circuit is open.
TROUBLE SYMPTOM:

The ABS warning light turns on or off normally but the
start code cannot be read out in the diagnostic mode.
WIRING DIAGRAM:
B4M1230
25
4-4dBRAKES [ABS 5.3i TYPE]
7. Diagnostics Chart for ABS Warning Light Circuit and Diagnosis Circuit Failure

B4M0800A
7C1
CHECK DIAGNOSIS TERMINAL.
Measure resistance between diagnosis terminals (B81)
and chassis ground.
Terminals
Diagnosis terminal (A)—Chassis ground:
Diagnosis terminal (B)—Chassis ground:
: Is the resistance less than 0.5Ω?
: Go to step7C2.
: Repair diagnosis terminal harness.
B4M1233A
7C2
CHECK DIAGNOSIS LINE.
1) Turn ignition switch to OFF.
2) Connect diagnosis terminal to diagnosis connector
(B82) No. 6.
3) Disconnect connector from ABSCM&H/U.
4) Measure resistance between ABSCM&H/U connector
and chassis ground.
Connector & terminal
(F49) No. 4—Chassis ground:
: Is the resistance less than 0.5Ω?
: Go to step7C3.
: Repair harness connector between ABSCM&H/U
and diagnosis connector.
7C3CHECK POOR CONTACT IN ABSCM&H/U
CONNECTOR.
: Is there poor contact in ABSCM&H/U con-
nector? <Ref. to FOREWORD [T3C1].>
: Repair connector.
: Replace ABSCM&H/U.
26
4-4dBRAKES [ABS 5.3i TYPE]
7. Diagnostics Chart for ABS Warning Light Circuit and Diagnosis Circuit Failure

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

8E8CHECK INSTALLATION OF TONE
WHEEL.
Tightening torque:
13±3 N⋅m (1.3±0.3 kg-m, 9±2.2 ft-lb)
: Are the tone wheel installation bolts tight-
ened securely?
: Go to step8E9.
: Tighten tone wheel installation bolts securely.
G4M0700
8E9
CHECK ABS SENSOR GAP.
Measure tone wheel-to-pole piece gap over entire perim-
eter of the wheel.
: Is the gap within the specifications shown
in the following table?
SpecificationsFront wheel Rear wheel
0.9—1.4 mm
(0.035—0.055 in)0.7—1.2 mm
(0.028—0.047 in)
G4M0701
: Go to step8E10.
: Adjust the gap.
NOTE:
Adjust the gap using spacers (Part No. 26755AA000). If
spacers cannot correct the gap, replace worn sensor or
worn tone wheel.
8E10
CHECK HUB RUNOUT.
Measure hub runout.
: Is the runout less than 0.05 mm (0.0020 in)?
: Go to step8E11.
: Repair hub.
32
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light

B4M0818E
B4M1042C
8E11CHECK GROUND SHORT OF ABS SEN-
SOR.
1) Turn ignition switch to ON.
2) Measure resistance 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 resistance more than 1 MΩ?
: Go to step8E12.
: Replace ABS sensor and ABSCM&H/U.
B4M1241A
8E12
CHECK GROUND SHORT OF HARNESS.
1) Turn ignition switch to OFF.
2) Connect connector to ABS sensor.
3) Measure resistance between ABSCM&H/U connector
terminal 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 resistance more than 1 MΩ?
: Go to step8E13.
: Repair harness between ABSCM&H/U and ABS
sensor.
Replace ABSCM&H/U.
8E13CHECK POOR CONTACT IN CONNEC-
TORS.
: Is there poor contact in connectors between
ABSCM&H/U and ABS sensor? <Ref. to
FOREWORD [T3C1].>
: Repair connector.
: Go to step8E14.
33
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light

8E14
CHECK ABSCM&H/U.
1) Connect all connectors.
2) Erase the memory.
3) Perform inspection mode.
4) Read out the trouble code.
: Is the same trouble code as in the current
diagnosis still being output?
: Replace ABSCM&H/U.
: Go to step8E15.
8E15CHECK ANY OTHER TROUBLE CODES
APPEARANCE.
: Are other trouble codes being output?
: Proceed with the diagnosis corresponding to the
trouble code.
: A temporary poor contact.
NOTE:
Check harness and connectors between ABSCM&H/U and
ABS sensor.
34
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light