1997 SUBARU LEGACY check engine

B4M0430
10W1
CHECK GENERATOR.
1) Start engine.
2) Idling after warm-up.
3) Measure voltage between generator B terminal and
chassis ground.
Terminal
Generator B terminal—Chassis ground:
: Is the voltage between 10 V and 15 V?
: Go to step10W2.
: Repair generator.
10W2
CHECK BATTERY TERMINAL.
Turn ignition switch to OFF.
: Are the positive and negative battery termi-
nals tightly clamped?
: Go to step10W3.
: Tighten the clamp of terminal.
B4M1234A
10W3CHECK INPUT VOLTAGE OF
ABSCM&H/U.
1) Disconnect connector from ABSCM&H/U.
2) Run the engine at idle.
3) Measure voltage between ABSCM&H/U connector and
chassis ground.
Connector & terminal
(F49) No. 1 (+)—Chassis ground ():
: Is the voltage between 10 V and 15 V?
: Go to step10W4.
: Repair harness connector between battery, igni-
tion switch and ABSCM&H/U.
136
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor

B4M0430
10X1
CHECK GENERATOR.
1) Start engine.
2) Idling after warm-up.
3) Measure voltage between generator B terminal and
chassis ground.
Terminal
Generator B terminal—Chassis ground:
: Is the voltage between 10 V and 17 V?
: Go to step10X2.
: Repair generator.
10X2
CHECK BATTERY TERMINAL.
Turn ignition switch to OFF.
: Are the positive and negative battery termi-
nals tightly clamped?
: Go to step10X3.
: Tighten the clamp of terminal.
B4M1234A
10X3CHECK INPUT VOLTAGE OF
ABSCM&H/U.
1) Disconnect connector from ABSCM&H/U.
2) Run the engine at idle.
3) Measure voltage between ABSCM&H/U connector and
chassis ground.
Connector & terminal
(F49) No. 1 (+)—Chassis ground ():
: Is the voltage between 10 V and 17 V?
: Go to step10X4.
: Repair harness connector between battery, igni-
tion switch and ABSCM&H/U.
139
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor

B4M1254A
10AA1CHECK INPUT VOLTAGE OF
ABSCM&H/U.
1) Turn ignition switch to OFF.
2) Disconnect connector from ABSCM&H/U.
3) Run the engine at idle.
4) Measure voltage between ABSCM&H/U connector and
chassis ground.
Connector & terminal
(F49) No. 1 (+)—Chassis ground ():
(F49) No. 24 (+)—Chassis ground ():
: Is the voltage between 10 V and 15 V?
: Go to step10AA2.
: Repair harness connector between battery and
ABSCM&H/U.
B4M1243A
10AA2CHECK GROUND CIRCUIT OF
ABSCM&H/U.
1) Turn ignition switch to OFF.
2) Measure resistance between ABSCM&H/U connector
and chassis ground.
Connector & terminal
(F49) No. 23—Chassis ground:
: Is the resistance less than 0.5Ω?
: Go to step10AA3.
: Repair ABSCM&H/U ground harness.
10AA3CHECK POOR CONTACT IN CONNEC-
TORS.
: Is there poor contact in connectors between
generator, battery and ABSCM&H/U? to FOREWORD [T3C1].>
: Repair connector.
: Go to step10AA4.
148
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor

B4M1234A
10AE3CHECK INPUT VOLTAGE OF
ABSCM&H/U.
1) Run the engine at idle.
2) Measure voltage between ABSCM&H/U connector and
chassis ground.
Connector & terminal
(F49) No. 1 (+)—Chassis ground ():
: Is the voltage between 10 V and 15 V?
: Go to step10AE4.
: Repair harness connector between battery, igni-
tion switch and ABSCM&H/U.
B4M1243A
10AE4CHECK GROUND CIRCUIT OF
ABSCM&H/U.
1) Turn ignition switch to OFF.
2) Measure resistance between ABSCM&H/U connector
and chassis ground.
Connector & terminal
(F49) No. 23—Chassis ground:
: Is the resistance less than 0.5Ω?
: Go to step10AE5.
: Repair ABSCM&H/U ground harness.
10AE5
CHECK MOTOR OPERATION.
Operate the sequence control.
NOTE:
Use the diagnosis connector to operate the sequence con-
trol.
: Can motor revolution noise (buzz) be heard
when carrying out the sequence control?
: Go to step10AE6.
: Replace hydraulic unit.
159
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor

B5M0115B
B: ON-BOARD DIAGNOSTIC
When the airbag system is in functioning condition, the
airbag warning light will remain on for 8 seconds and go out
when the ignition switch is set to ON.
If there is any malfunction, the airbag warning light will
either stay on or off continuously. In such cases, perform
on-board diagnostic in accordance with the specified pro-
cedure to determine trouble codes.
1) Turn ignition switch ON (with engine OFF).
2) Connect DIAG. terminal

1to No. 1 terminal of diagno-
sis connector

2located below lower cover.
3) Check in accordance with the trouble code indicated by
the AIRBAG warning light, and record the trouble codes.
4) Turn the ignition switch “OFF” and remove the DIAG.
terminal from No.1 terminal of diagnosis connector.
B5M0116B
C: CLEAR MEMORY
After eliminating problem as per trouble code, clear
memory as follows:
Make sure ignition switch is ON (and engine off). Connect
one DIAG. terminal

1on diagnosis connector
2terminal
No. 1.
While warning light is flashing, connect the other DIAG.
terminal

3on terminal No. 2 for at least three seconds.
After memory is cleared, normal warning light flashing rate
resumes. (Warning light flashes every 0.6 seconds ON-
OFF operation.) Memory cannot be cleared if any problem
exists.
After clear memory and then DIAG. terminals

1and
3,
extract from diagnosis connector

2.
9
5-5SUPPLEMENTAL RESTRAINT SYSTEM
4. Diagnostics Chart for On-board Diagnostic System

G5M0559
1. AIRBAG CONTROL MODULE INSPECTION
1) Disconnect connector (AB6) from airbag control module
, and connect it to test harness B2
connector (8B).
2) Connect battery ground cable and turn ignition switch
“ON”(engine off).
3) Measure voltage across connector (5B) terminal and
body.
(5B) Terminal / Specified voltage:
No. 5—Body / 10 V, or more
2. AIRBAG MAIN HARNESS INSPECTION
1) Go to step 2) below after performing diagnostics on air-
bag system as per flowchart under“1. AIRBAG CON-
TROL MODULE INSPECTION”previously outlined.
2) Turn ignition switch“OFF”, disconnect battery ground
cable and then wait at least 20 seconds.
B5M0119B
3) Disconnect connector (AB1) from body harness con-
nector (B31) at front lower pillar, and connect connector
(AB1) to test harness A connector (2A).
4) Measure resistance between test harness A connector
(5A) and test harness B2 connector (5B) terminals.
Connector & terminal / Specified resistance:
(5A) No. 9—(5B) No.5/10Ω, or less
5) Measure resistance between each terminal of connec-
tors (5A) and (5B) and body.
(5A) Terminal / Specified resistance:
No. 9—Body/10kΩ, or more
(5B) Terminal / Specified resistance:
No. 5—Body/10kΩ, or more
G5M0453
3. FUSE No. 16 INSPECTION
Make sure ignition switch is turned“OFF”, then remove and
visually check fuse No. 16.
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5-5SUPPLEMENTAL RESTRAINT SYSTEM
5. Diagnostics Chart with Trouble Code

B5M0123B
2. INSPECTION OF BODY HARNESS, CONNECTOR
AND AIRBAG WARNING LIGHT
1) Turn ignition switch“OFF”and connect body harness
connector (B31) to test connector A connector (1A).
G5M0455
2) Connect battery ground cable and turn ignition switch
“ON”, (engine off) and connect connectors (3A) and (4A) to
check if warning light goes out. If it does, go to step 4)
below. If it remains on, check body harness and repair if
necessary.
B5M0124A
3) If body harness is satisfactory, replace airbag warning
light module

1. After problem has been eliminated, discon-
nect connectors (3A) and (4A).
G5M0559
4) Turn ignition switch“OFF”, disconnect battery ground
cable and then wait at least 20 seconds, and re-connect
connectors (AB1) and (B31).
5) Remove instrument panel lower cover and disconnect
(AB3) with (AB8), then disconnect connector (AB6) from
airbag control module, and connect
it to test harness B2 connector (8B).
G5M0458
6) Connect battery ground cable and turn ignition switch
“ON,”(engine off) and connect connectors (6B) and (7B) to
check if warning light goes out. If it does, go to“3.
GROUNDING CIRCUIT INSPECTION”. If it remains on,
replace airbag main harness. After problem has been
eliminated, disconnect connectors (6B) and (7B).
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5-5SUPPLEMENTAL RESTRAINT SYSTEM
5. Diagnostics Chart with Trouble Code

O: AIRBAG WARNING LIGHT REMAINS OFF.
DIAGNOSIS:
Fuse No. 15 is blown.
Body harness circuit is open.
Airbag warning light is faulty.
Airbag main harness is faulty.
Airbag control module is faulty.
1. Fuse No. 15 inspection
O.K.
Not O.K.
Replace fuse No. 15.
2. Body harness inspection
O.K.
Not O.K.
Repair body harness.
3. Airbag warning light module (in combination
meter) inspection
O.K.
Not O.K.
Replace airbag warning light module.
4. Airbag main harness inspection
O.K.
Not O.K.
Replace airbag main harness.
Replace airbag control module.
CAUTION:
Before performing diagnostics on airbag system, turn
ignition switch“OFF”, disconnect battery ground
terminal, and then wait at least 20 seconds.
G5M0460
1. FUSE No. 15 INSPECTION
1) Remove and visually check fuse No. 15.
2) If fuse is blown, replace it with a new one. After con-
necting battery cable and turning ignition switch“ON”,ifit
blows again, proceed to“2. BODY HARNESS INSPEC-
TION”.
2. BODY HARNESS INSPECTION
Turn ignition switch“ON”(engine off) to make sure other
warning lights (in combination meter) illuminate. If they do
not, check body harness.




38
5-5SUPPLEMENTAL RESTRAINT SYSTEM
5. Diagnostics Chart with Trouble Code