check engine light SUBARU LEGACY 1997 Service Manual Online

7A1CHECK IF OTHER WARNING LIGHTS
TURN ON.
Turn ignition switch to ON (engine OFF).
: Do other warning lights turn on?
: Go to step7A2.
: Repair combination meter.
7A2
CHECK ABS WARNING LIGHT BULB.
1) Turn ignition switch to OFF.
2) Remove combination meter.
3) Remove ABS warning light bulb from combination
meter.
: Is ABS warning light bulb OK?
: Go to step7A3.
: Replace ABS warning light bulb.
B4M1273A
7A3CHECK BATTERY SHORT OF ABS
WARNING LIGHT HARNESS.
1) Disconnect connector (B100) from connector (F2).
2) Measure voltage between connector (B100) and chas-
sis ground.
Connector & terminal
(B100) No. 9 (+) — Chassis ground ():
: Is the voltage less than 3 V?
: Go to step7A4.
: Repair warning light harness.
17
4-4dBRAKES [ABS 5.3i TYPE]
7. Diagnostics Chart for ABS Warning Light Circuit and Diagnosis Circuit Failure

B4M0430
7B4
CHECK GENERATOR.
1) Start the engine.
2) Idle the engine.
3) Measure voltage between generator and chassis
ground.
Terminal
Generator B terminal (+)—Chassis ground ():
: Is the voltage between 10 and 15 V?
: Go to step7B5.
: Repair generator.
7B5
CHECK BATTERY TERMINAL.
Turn ignition switch to OFF.
: Is there poor contact at battery terminal?
: Repair battery terminal.
: Go to step7B6.
B4M1234A
7B6
CHECK POWER SUPPLY OF ABSCM.
1) Disconnect connector from ABSCM&H/U.
2) Start engine.
3) Idle the engine.
4) Measure voltage between ABSCM&H/U connector and
chassis ground.
Connector & terminal
(F49) No. 1 (+)—Chassis ground ():
: Is the voltage between 10 and 15 V?
: Go to step7B7.
: Repair ABSCM&H/U power supply circuit.
7B7
CHECK WIRING HARNESS.
1) Disconnect connector (F2) from connector (B100).
2) Turn ignition switch to ON.
: Does the ABS warning light remain off?
: Go to step7B8.
: Repair front wiring harness.
B4M1235A
7B8
CHECK PROJECTION AT ABSCM&H/U.
1) Turn ignition switch to OFF.
2) Check for broken projection at the ABSCM&H/U termi-
nal.
: Are the projection broken?
: Go to step7B9.
: Replace ABSCM&H/U.
23
4-4dBRAKES [ABS 5.3i TYPE]
7. Diagnostics Chart for ABS Warning Light Circuit and Diagnosis Circuit Failure

B4M1234A
8N1CHECK 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 step8N2.
: Repair harness connector between battery, igni-
tion switch and ABSCM&H/U.
B4M1243A
8N2CHECK 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 step8N3.
: Repair ABSCM&H/U ground harness.
8N3CHECK 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 step8N4.
48
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light

B4M1234A
8R1CHECK 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 step8R2.
: Repair harness connector between battery, igni-
tion switch and ABSCM&H/U.
B4M1243A
8R2CHECK 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 step8R3.
: Repair ABSCM&H/U ground harness.
8R3CHECK 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 step8R4.
8R4
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 step8R5.
51
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light

B4M0430
8T1
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 step8T2.
: Repair generator.
8T2
CHECK BATTERY TERMINAL.
Turn ignition switch to OFF.
: Are the positive and negative battery termi-
nals tightly clamped?
: Go to step8T3.
: Tighten the clamp of terminal.
B4M1234A
8T3CHECK 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 step8T4.
: Repair harness connector between battery, igni-
tion switch and ABSCM&H/U.
57
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light

B4M1254A
8V1CHECK 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 step8V2.
: Repair harness connector between battery and
ABSCM&H/U.
B4M1243A
8V2CHECK 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 step8V3.
: Repair ABSCM&H/U ground harness.
B4M1272A
8V3
CHECK VALVE RELAY IN ABSCM&H/U.
Measure resistance between ABSCM&H/U and terminals.
Terminals
No. 23 (+)—No. 24 ():
: Is the resistance more than 1 MΩ?
: Go to step8V4.
: Replace ABSCM&H/U.
64
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light

B4M1234A
8W3CHECK 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 step8W4.
: Repair harness connector between battery, igni-
tion switch and ABSCM&H/U.
B4M1243A
8W4CHECK 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 step8W5.
: Repair ABSCM&H/U ground harness.
8W5
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 step8W6.
: Replace ABSCM&H/U.
68
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light

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

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).
36
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