1996 SUBARU LEGACY Brakes

K: TROUBLE CODE 51
—ABNORMAL VALVE RELAY—
DIAGNOSIS:

Faulty valve relay
TROUBLE SYMPTOM:

ABS does not operate.
8K1.Check resistance of valve relay.
8K2.Check contact point of valve relay.
8K3.Check short of valve relay.
8K4.Check power supply voltage at valve relay
contact point.
8K5.Check ground circuit of relay box.
8K6.Check broken wire and ground short in power
supply circuit of relay box.
8K7.Check broken wire in contact point circuit of
relay box.
8K8.Check ground short in contact point circuit of
relay box.
8K9.Check battery short in contact point circuit of
relay box.
8K10.Check diode of relay box.
8K11.Check broken wire in ground circuit of relay
box.
8K12.Check battery short in ground circuit of relay
box.
8K13.Check broken wire in control circuit of relay
box.
8K14.Check ground short in control circuit of relay
box.
8K15.Check battery short in control circuit of relay
box.
Continues to next page.















75
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

From the former page.
8K16.
Check broken wire in control system harness
of valve relay.
8K17.Check ground short in control system harness
of valve relay.
8K18.Check battery short in control system harness
of valve relay.
8K19.Check resistance of inlet solenoid valve.
8K20.Check resistance of outlet solenoid valve.
8K21.Check ground short of solenoid valve.
8K22.Check battery short of solenoid valve.
8K23.Check battery short of harness.
8K24.Check ground short of harness.
8K25.Check harness connector between ABSCM
and hydraulic unit.
8K26.Check poor contact in connector between
ABSCM and hydraulic unit.
8K27.Check ABSCM.












76
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

WIRING DIAGRAM:
B4M1048
B4M0858A
8K1
CHECK RESISTANCE OF VALVE RELAY.
1) Turn ignition switch to OFF.
2) Remove valve relay from relay box.
3) Measure resistance between valve relay terminals.
: Terminals
No. 85—No. 86
Is resistance 103±10Ω?
: Go to step8K2.
: Replace valve relay.
77
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

B4M0811A
8K2CHECK CONTACT POINT OF VALVE
RELAY.
1) Connect battery to valve relay terminals No. 85 and No.
86.
2) Measure resistance between valve relay terminals.
: Terminals
No. 30—No. 87
Is resistance less than 0.5Ω?
: Go to next.
: Replace valve relay.
: Terminals
No. 30—No. 87a
Is resistance more than 1 MΩ?
: Go to next step.
: Replace valve relay.
B4M0798A
3) Disconnect battery from valve relay terminals.
4) Measure resistance between valve relay terminals.
: Terminals
No. 30—No. 87
Is resistance more than 1 MΩ?
: Go to next.
: Replace valve relay.
: Terminals
No. 30—No. 87a
Is resistance less than 0.5Ω?
: Go to step8K3.
: Replace valve relay.
B4M0861A
8K3
CHECK SHORT OF VALVE RELAY.
Measure resistance between valve relay terminals.
: Terminals
No. 86—No. 87
No. 86—No. 87a
Is resistance more than 1 MΩ?
: Go to step8K4.
: Replace valve relay.
78
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

B4M0862B
8K4CHECK POWER SUPPLY VOLTAGE AT
VALVE RELAY CONTACT POINT.
1) Disconnect connector (F8) from relay box.
2) Measure voltage between relay box connector and
chassis ground.
: Connector & terminal
(F8) No. 1 (+)—Chassis ground ()
Is voltage 10—13 V?
: Go to step8K5.
: Repair harness connector between battery and
relay box. Check fuse No. 19.
B4M0863B
8K5CHECK GROUND CIRCUIT OF RELAY
BOX.
1) Disconnect connector (F50) from relay box.
2) Measure resistance between relay box connector and
chassis ground.
: Connector & terminal
(F50) No. 3—Chassis ground
Is resistance less than 0.5Ω?
: Go to step8K6.
: Repair relay box ground harness.
79
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

B4M0864
8K6CHECK BROKEN WIRE AND GROUND
SHORT IN POWER SUPPLY CIRCUIT OF
RELAY BOX.
1) Disconnect connector (ABS1) from hydraulic unit.
2) Connect connector (F8) to relay box.
3) Measure voltage of relay box.
: Connector & terminal
Valve relay installing point No. 87—Chas-
sis ground
Is voltage 10—13 V?
: Go to step8K7.
: Replace relay box. Check fuse No. 19.
B4M0865A
8K7CHECK BROKEN WIRE IN CONTACT
POINT CIRCUIT OF RELAY BOX.
Measure resistance between hydraulic unit connector and
valve relay installing point.
: Connector & terminal
(ABS1) No. 2—Valve relay installing point
No. 30
Is resistance less than 0.5Ω?
: Go to step8K8.
: Replace relay box.
B4M0866A
8K8CHECK GROUND SHORT IN CONTACT
POINT CIRCUIT OF RELAY BOX.
Measure resistance between hydraulic unit connector and
chassis ground.
: Connector & terminal
(ABS1) No. 2—Chassis ground
Is resistance more than 1 MΩ?
: Go to step8K9.
: Replace relay box. Check fuse SBF6.
80
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

B4M0867A
8K9CHECK BATTERY SHORT IN CONTACT
POINT CIRCUIT OF RELAY BOX.
1) Disconnect connector from ABSCM.
2) Turn ignition switch to ON.
3) Measure voltage between hydraulic unit connector and
chassis ground.
: Connector & terminal
(ABS1) No. 2 (+)—Chassis ground ()
Is voltage 0 V?
: Go to next step.
: Replace relay box. Check fuse No. 19 and SBF6.
4) Turn ignition switch to OFF.
5) Measure voltage between hydraulic unit connector and
chassis ground.
: Connector & terminal
(ABS1) No. 2 (+)—Chassis ground ()
Is voltage 0 V?
: Go to step8K10.
: Replace relay box. Check fuse No. 19 and SBF6.
B4M0868B
8K10
CHECK DIODE OF RELAY BOX.
Measure resistance between relay box connector and
valve relay installing point.
: Connector & terminal
Valve relay installing point No. 30 (+)—To
(F50) No. 2 ()
Is resistance more than 1 MΩ?
: Go to step8K11.
: Replace relay box.
B4M0869B
8K11CHECK BROKEN WIRE IN GROUND CIR-
CUIT OF RELAY BOX.
Measure resistance between relay box connector and
valve relay installing point.
: Connector & terminal
To (F50) No. 3—Valve relay installing point
No. 87a
Is resistance less than 0.5Ω?
: Go to step8K12.
: Replace relay box.
81
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

B4M0870B
8K12CHECK BATTERY SHORT IN GROUND
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. 3 (+)—Chassis ground ()
Is voltage 0 V?
: Go to next step.
: Replace relay box and check all fuses.
3) Turn ignition switch to OFF.
4) Measure voltage between relay box connector and
chassis ground.
: Connector & terminal
To (F50) No. 3 (+)—Chassis ground ()
Is voltage 0 V?
: Go to step8K13.
: Replace relay box and check all fuses.
B4M0871B
8K13CHECK BROKEN WIRE IN CONTROL
CIRCUIT OF RELAY BOX.
1) Install valve relay to relay box.
2) Measure resistance between relay box connector termi-
nals.
: Connector & terminal
To (F50) No. 1—No. 5
Is resistance 103±10Ω?
: Go to step8K14.
: Replace relay box.
B4M0872B
8K14CHECK GROUND SHORT IN CONTROL
CIRCUIT OF RELAY BOX.
Measure resistance between relay box connector and
chassis ground.
: Connector & terminal
To (F50) No. 1—Chassis ground
Is resistance more than 1 MΩ?
: Go to step8K15.
: Replace relay box and check all fuses.
82
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code