SUBARU LEGACY 1997 Service Repair Manual

B4M0886A
10AD1
CHECK RESISTANCE OF MOTOR RELAY.
1) Turn ignition switch to OFF.
2) Remove motor relay from relay box.
3) Measure resistance between motor relay terminals.
: Terminals
No. 85—No. 86
Is resistance 80±10Ω?
: Go to step10AD2.
: Replace motor relay.
B4M0887A
10AD2CHECK CONTACT POINT OF MOTOR
RELAY.
1) Connect battery to motor relay terminals No. 85 and No.
86.
2) Measure resistance between motor relay terminals.
: Terminals
No. 30—No. 87
Is resistance less than 0.5Ω?
: Go to next step.
: Replace motor relay.
B4M0888A
3) Disconnect battery from motor relay terminals.
4) Measure resistance between motor relay terminals.
: Terminals
No. 30—No. 87
Is resistance more than 1 MΩ?
: Go to step10AD3.
: Replace motor relay.
B4M0889A
10AD3
CHECK SHORT OF MOTOR RELAY.
Measure resistance between motor relay terminals.
: Terminals
No. 85—No. 30
No. 85—No. 87
Is resistance more than 1 MΩ?
: Go to step10AD4.
: Replace motor relay.
226
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor

B4M0890B
10AD4CHECK INPUT VOLTAGE OF RELAY
BOX.
1) Disconnect connector (F8) from relay box.
2) Measure voltage between relay box connector and
chassis ground.
: Connector & terminal
(F8) No. 2 (+)—Chassis ground ()
Is voltage 10—13 V?
: Go to step10AD5.
: Repair harness connector between battery and
relay box. Check fuse SBF6.
B4M0891
10AD5CHECK INPUT VOLTAGE OF MOTOR
RELAY.
1) Connect connector (F8) to relay box.
2) Measure voltage between relay box and chassis
ground.
: Connector & terminal
Relay installing point No. 87 (+)—Chassis
ground ()
Is voltage 10—13 V?
: Go to step10AD6.
: Replace relay box and fuse SBF6.
227
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor

B4M0892A
10AD6CHECK BROKEN WIRE IN CONTACT
POINT CIRCUIT OF RELAY BOX.
1) Disconnect connector (ABS1) from hydraulic unit.
2) Measure resistance between hydraulic unit and motor
relay installing portion.
: Connector & terminal
(ABS1) No. 1—Motor relay installing por-
tion No. 30
Is resistance less than 0.5Ω?
: Go to step10AD7.
: Replace relay box.
B4M0893A
10AD7CHECK GROUND SHORT IN CONTACT
POINT CIRCUIT OF RELAY BOX.
Measure resistance between hydraulic unit and chassis
ground.
: Connector & terminal
(ABS1) No. 1—Chassis ground
Is resistance more than 1 MΩ?
: Go to step10AD8.
: Replace relay box. Check fuse No. 19.
B4M0795B
10AD8CHECK BROKEN WIRE IN MONITOR
SYSTEM CIRCUIT OF RELAY BOX.
1) Disconnect connector (F50) from relay box.
2) Measure resistance between relay box connector and
motor relay installing point.
: Connector & terminal
To (F50) No. 6—Motor relay installing point
No. 30
Is resistance less than 0.5Ω?
: Go to step10AD9.
: Replace relay box.
228
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor

B4M0894
10AD9CHECK BROKEN WIRE IN CONTROL
CIRCUIT OF RELAY BOX.
1) Remove valve relay from relay box.
2) Measure resistance between motor relay installing point
and valve relay installing point.
: Connector & terminal
Motor relay installing point No. 86—Valve
relay installing point No. 30
Is resistance less than 0.5Ω?
: Go to next step.
: Replace relay box.
B4M0895B
3) Measure resistance between motor relay installing point
and relay box connector.
: Connector & terminal
Motor relay installing point No. 86—To
(F50) No. 4
Is resistance less than 0.5Ω?
: Go to step10AD10.
: Replace relay box.
B4M0896
10AD10CHECK GROUND SHORT IN CONTROL
CIRCUIT OF RELAY BOX.
Measure resistance between relay box and chassis
ground.
: Connector & terminal
Motor relay installing point No. 86—Chas-
sis ground
Motor relay installing point No. 85—Chas-
sis ground
Is resistance more than 1 MΩ?
: Go to step10AD11.
: Replace relay box. Check fuse No. 19.
229
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor

B4M0897
10AD11CHECK BATTERY SHORT IN CONTROL
CIRCUIT OF RELAY BOX.
1) Disconnect connector from ABSCM.
2) Turn ignition switch to ON.
3) Measure voltage between motor relay installing point
and chassis ground.
: Connector & terminal
Motor relay installing point No. 85 (+)—
Chassis ground ()
Motor relay installing point No. 86 (+)—
Chassis ground ().
Is voltage 0 V?
: Go to next step.
: Replace relay box and check all fuses.
4) Turn ignition switch to OFF.
5) Measure voltage between motor relay installing point
and chassis ground.
: Connector & terminal
Motor relay installing point No. 85 (+)—
Chassis ground
Motor relay installing point No. 86 (+)—
Chassis ground ()
Is voltage 0 V?
: Go to step10AD12.
: Replace relay box and check all fuses.
B4M0898B
10AD12CHECK BROKEN WIRE IN MONITOR
SYSTEM HARNESS.
1) Connect between terminals No. 10 and No. 1 of
ABSCM connector (F49) with a lead wire.
2) Measure resistance between relay box connector and
chassis ground.
: Connector & terminal
(F50) No. 6—Chassis ground
Is resistance less than 0.5Ω?
: Go to step10AD13.
: Repair harness connector between ABSCM and
relay box.
230
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor

B4M0899A
10AD13CHECK BROKEN WIRE IN RELAY CON-
TROL SYSTEM HARNESS.
1) Connect valve relay and motor relay to relay box.
2) Connect connector (F50) to relay box.
3) Connect connector to hydraulic unit.
4) Measure resistance between ABSCM connector and
chassis ground.
: Connector & terminal
(F49) No. 22—Chassis ground
Is resistance 80±10Ω?
: Go to step10AD14.
: Repair harness connector between ABSCM and
relay box.
B4M0900A
10AD14CHECK GROUND SHORT BETWEEN
RELAY BOX AND ABSCM.
1) Disconnect connector (F50) from relay box.
2) Measure resistance between ABSCM connector and
chassis ground.
: Connector & terminal
(F49) No. 22—Chassis ground
(F49) No. 10—Chassis ground
Is resistance more than 1 MΩ?
: Go to step10AD15.
: Repair harness between ABSCM and relay box.
Check fuse No. 19 and SBF6.
231
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor

B4M0901A
10AD15CHECK BATTERY SHORT BETWEEN
RELAY BOX AND ABSCM.
1) Turn ignition switch to ON.
2) Measure voltage between ABSCM and chassis ground.
: Connector & terminal
(F49) No. 22 (+)—Chassis ground ()
(F49) No. 10 (+)—Chassis ground ()
Is voltage 0 V?
: Go to next step.
: Repair harness between relay box and ABSCM.
Check fuse SBF6.
3) Turn ignition switch to OFF.
4) Measure voltage between ABSCM and chassis ground.
: Connector & terminal
(F49) No. 22 (+)—Chassis ground ()
(F49) No. 10 (+)—Chassis ground ()
Is voltage 0 V?
: Go to step10AD16.
: Repair harness between relay box and ABSCM.
Check fuse SBF6.
B4M0902A
10AD16CHECK GROUND SHORT AT ABSCM
MONITOR TERMINAL.
Measure resistance between ABSCM terminals.
: Connector & terminal
To (F49) No. 10—No. 1
Is resistance more than 1 MΩ?
: Go to step10AD17.
: Replace ABSCM.
B4M0904A
10AD17CHECK ABSCM MOTOR DRIVE TERMI-
NAL.
1) Disconnect connector cover from ABSCM connector.
<Ref. to 4-4c [T8C3] steps 5) to 8).>
2) Connect all connectors.
3) Measure voltage between ABSCM connector terminals.
4) Operate the check sequence. <Ref. to 4-4 [W22D1].>
: Connector & terminals
(F49) No. 22 (+)—No.1()
Does the voltage drop from 10—13Vto
less than 1.5 V, and rise to 10—13 V again
when carrying out the check sequence?
: Go to step10AD18.
: Replace ABSCM.
232
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor

B4M0905A
10AD18
CHECK MOTOR OPERATION.
1) Measure voltage between ABSCM connector terminal.
2) Operate the check sequence. <Ref. to 4-4 [W22D1].>
: Connector & terminals
(F49) No. 10 (+)—No.1()
Does the voltage raise from less than 1.5 V
to 10—13 V, and return to less than 1.5 V
again when carrying out the check
sequence?
Can motor revolution noise (buzz) be heard
when carrying out the check sequence?
: Go to step10AD19.
: Replace hydraulic unit.
10AD19CHECK POOR CONTACT IN CONNEC-
TOR BETWEEN HYDRAULIC UNIT,
RELAY BOX AND ABSCM.
: Is there poor contact in connector between
hydraulic unit, relay box and ABSCM?
: Repair connector.
: Go to step10AD20.
10AD20
CHECK ABSCM.
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.
: Go to next.
: Are other trouble codes being output?
: Proceed with the diagnosis corresponding to the
trouble code.
: A temporary poor contact.
233
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor

B4M0970
AE: 52 M. RELAY ON
—MOTOR RELAY ON FAILURE—
DIAGNOSIS:

Faulty motor

Faulty motor relay

Faulty harness connector
TROUBLE SYMPTOM:

ABS does not operate.
10AE1.Check resistance of motor relay.
10AE2.Check contact point of motor relay.
10AE3.Check short of motor relay.
10AE4.Check battery short in contact point circuit of
relay box.
10AE5.Check ground short in control circuit of relay
box.
10AE6.Check ground short between relay box and
ABSCM.
10AE7.Check battery short between relay box and
ABSCM.
10AE8.Check battery short at ABSCM monitor
terminal.
10AE9.Check motor ground.
10AE10.Check ABSCM motor drive terminal.
10AE11.Check motor operation.
10AE12.Check poor contact in connector between
hydraulic unit, relay box and ABSCM.
10AE13.Check ABSCM.












234
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor

WIRING DIAGRAM:
B4M1049
B4M0886A
10AE1
CHECK RESISTANCE OF MOTOR RELAY.
1) Turn ignition switch to OFF.
2) Remove motor relay from relay box.
3) Measure resistance between motor relay terminals.
: Terminals
No. 85—No. 86
Is resistance 80±10Ω?
: Go to step10AE2.
: Replace motor relay.
235
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor