1997 SUBARU LEGACY battery

B4M0873B
8K15CHECK BATTERY SHORT IN CONTROL
CIRCUIT OF RELAY BOX.
1) Turn ignition switch to ON.
2) Measure voltage between relay box connector and
chassis ground.
: Connector & terminal
To (F50) No. 1 (+)—Chassis ground ()
Is voltage 0 V?
: Go to next step.
: Replace relay box. Check fuse No. 19 and
SBF45A.
3) Turn ignition switch to OFF.
4) Measure voltage between relay box connector and
chassis ground.
: Connector & terminal
To (F50) No. 1 (+)—Chassis ground ()
Is voltage 0 V?
: Go to step8K16.
: Replace relay box. Check fuse No. 19 and
SBF45A.
B4M0874A
8K16CHECK BROKEN WIRE IN CONTROL
SYSTEM HARNESS OF VALVE RELAY.
1) Connect connector (F50) to relay box.
2) Measure resistance between ABSCM connector termi-
nals.
: Connector & terminal
(F49) No. 27—No. 47
Is resistance 103±10Ω?
: Go to step8K17.
: Repair harness between ABSCM and relay box.
Check fuse No. 18.
B4M0875A
8K17CHECK GROUND SHORT IN CONTROL
SYSTEM HARNESS OF VALVE RELAY.
Measure resistance between ABSCM connector and chas-
sis ground.
: Connector & terminal
(F49) No. 27—Chassis ground
Is resistance more than 1 MΩ?
: Go to step8K18.
: Repair harness between ABSCM and relay box.
Check fuse No. 18.
83
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

B4M0876A
8K18CHECK BATTERY SHORT IN CONTROL
SYSTEM HARNESS OF VALVE RELAY.
1) Turn ignition switch to ON.
2) Measure voltage between ABSCM connector and chas-
sis ground.
: Connector & terminal
(F49) No. 27 (+)—Chassis ground ()
Is voltage 0 V?
: Go to next step.
: Repair harness between ABSCM and relay box
and check all fuses.
3) Turn ignition switch to OFF.
4) Measure voltage between ABSCM connector and chas-
sis ground.
: Connector & terminal
(F49) No. 27 (+)—Chassis ground ()
Is voltage 0 V?
: Go to step8K19.
: Repair harness between ABSCM and relay box
and check all fuses.
B4M0824B
8K19CHECK RESISTANCE OF INLET SOLE-
NOID VALVE.
1) Disconnect connector from hydraulic unit.
2) Measure resistance between hydraulic unit connector
terminals.
: Connector & terminal
To (F9) No. 4—to (ABS1) No. 2
To (F9) No. 1—to (ABS1) No. 2
To (F9) No. 2—to (ABS1) No. 2
To (F9) No. 3—to (ABS1) No. 2
Is resistance 8.5±0.7Ω?
: Go to step8K20.
: Replace hydraulic unit.
84
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

B4M0831B
8K20CHECK RESISTANCE OF OUTLET SOLE-
NOID VALVE.
Measure resistance between hydraulic unit connector ter-
minals.
: Connector & terminal
To (F9) No. 8—to (ABS1) No. 2
To (F9) No. 5—to (ABS1) No. 2
To (F9) No. 6—to (ABS1) No. 2
To (F9) No. 7—to (ABS1) No. 2
Is resistance 4.3±0.5Ω?
: Go to step8K21.
: Replace hydraulic unit.
B4M0879B
8K21CHECK GROUND SHORT OF SOLENOID
VA LV E .
Measure resistance between hydraulic unit connector and
chassis ground.
: Connector & terminal
To (F9) No. 4—Chassis ground
Is resistance more than 1 MΩ?
: Go to step8K22.
: Replace hydraulic unit and check all fuses.
B4M0880B
8K22CHECK BATTERY SHORT OF SOLENOID
VA LV E .
1) Turn ignition switch to ON.
2) Measure voltage between hydraulic unit connector and
chassis ground.
: Connector & terminal
To (F9) No. 4 (+)—Chassis ground ()
Is voltage 0 V?
: Go to next step.
: Replace hydraulic unit and check all fuses.
3) Turn ignition switch to OFF.
4) Measure voltage between hydraulic unit connector and
chassis ground.
: Connector & terminal
To (F9) No. 4 (+)—Chassis ground ()
Is voltage 0 V?
: Go to step8K23.
: Replace hydraulic unit and check all fuses.
85
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

B4M0881A
8K23
CHECK BATTERY SHORT OF HARNESS.
1) Disconnect connector from hydraulic unit.
2) Turn ignition switch to ON.
3) Measure voltage between ABSCM connector and chas-
sis ground.
: Connector & terminal
(F49) No. 30 (+)—Chassis ground ()
(F49) No. 24 (+)—Chassis ground ()
(F49) No. 23 (+)—Chassis ground ()
(F49) No. 31 (+)—Chassis ground ()
(F49) No. 3 (+)—Chassis ground ()
(F49) No. 51 (+)—Chassis ground ()
(F49) No. 50 (+)—Chassis ground ()
(F49) No. 4 (+)—Chassis ground ()
Is voltage 0 V?
: Go to next step.
: Repair harness between hydraulic unit and
ABSCM and check all fuses.
4) Turn ignition switch to OFF.
5) Measure voltage between ABSCM connector and chas-
sis ground.
: Connector & terminal
(F49) No. 30 (+)—Chassis ground ()
(F49) No. 24 (+)—Chassis ground ()
(F49) No. 23 (+)—Chassis ground ()
(F49) No. 31 (+)—Chassis ground ()
(F49) No. 3 (+)—Chassis ground ()
(F49) No. 51 (+)—Chassis ground ()
(F49) No. 50 (+)—Chassis ground ()
(F49) No. 4 (+)—Chassis ground ()
Is voltage 0 V?
: Go to step8K24.
: Repair harness between hydraulic unit and
ABSCM and check all fuses.
86
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

L: TROUBLE CODE 52
—ABNORMAL MOTOR AND/OR MOTOR
RELAY—
DIAGNOSIS:

Faulty motor

Faulty motor relay

Faulty harness connector
TROUBLE SYMPTOM:

ABS does not operate.
8L1.Check resistance of motor relay.
8L2.Check contact point of motor relay.
8L3.Check short of motor relay.
8L4.Check input voltage of relay box.
8L5.Check input voltage of motor relay.
8L6.Check broken wire in contact point circuit of
relay box.
8L7.Check ground short in contact point circuit of
relay box.
8L8.Check battery short in contact point circuit of
relay box.
8L9.Check broken wire in monitor system circuit of
relay box.
8L10.Check broken wire in control circuit of relay
box.
8L11.Check ground short in control circuit of relay
box.
8L12.Check battery short in control circuit of relay
box.
8L13.Check broken wire in monitor system harness.
8L14.Check broken wire in relay control system
harness.
8L15.Check ground short between relay box and
ABSCM.
Continues to next page.















89
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

From the former page.
8L16.
Check battery short between relay box and
ABSCM.
8L17.Check ground short at ABSCM monitor
terminal.
8L18.Check battery short at ABSCM monitor
terminal.
8L19.Check motor ground.
8L20.Check ABSCM motor drive terminal.
8L21.Check motor operation.
8L22.Check poor contact in connector between
hydraulic unit, relay box and ABSCM.
8L23.Check ABSCM.








90
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

B4M0886A
8L1
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 step8L2.
: Replace motor relay.
B4M0887A
8L2CHECK 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 step8L3.
: Replace motor relay.
92
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

B4M0889A
8L3
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 step8L4.
: Replace motor relay.
B4M0890B
8L4CHECK 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 step8L5.
: Repair harness connector between battery and
relay box. Check fuse SBF6.
B4M0891
8L5CHECK 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 more than 10 V?
: Go to step8L6.
: Replace relay box. Check fuse SBF6.
93
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code