engine SUBARU LEGACY 1997 Service Repair Manual

8. Diagnostics for Engine Starting
Failure
A: BASIC DIAGNOSTICS CHART
Inspection of starter motor circuit.
Inspection of ECM power supply and ground line.
Inspection of ignition control system.
Inspection of fuel pump circuit.
Inspection of fuel injector circuit.
Inspection of crankshaft position sensor circuit.
Inspection of camshaft position sensor circuit.
Inspection using Subaru select monitor or OBD-II
general scan tool or inspection using“9. General
Diagnostics Table.







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8. Diagnostics for Engine Starting Failure

B: STARTER MOTOR CIRCUIT
WIRING DIAGRAM:
B2M1047
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

OBD0724
8B1CHECK INPUT SIGNAL FOR STARTER
MOTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from starter motor.
3) Turn ignition switch to ST.
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8. Diagnostics for Engine Starting Failure

OBD0100A
4) Measure power supply voltage between starter motor
connector terminal and engine ground.
: Connector & terminal
(B14) No. 1 (+)—Engine ground ():
Is the voltage more than 10 V?
NOTE:

On AT vehicles, place the selector lever in the“P”or“N”
position.

On MT vehicles, depress the clutch pedal.
: Go to step8B2.
: Go to step8B3.
OBD0725
8B2CHECK GROUND CIRCUIT OF STARTER
MOTOR.
1) Turn ignition switch to OFF.
2) Disconnect terminal from starter motor.
3) Measure resistance of ground cable between ground
cable terminal and engine ground.
: Is resistance less than 5Ω?
: Check starter motor.
: Repair open circuit of ground cable.
8B3CHECK HARNESS BETWEEN BATTERY
AND IGNITION SWITCH CONNECTOR.
1) Turn ignition switch to OFF.
2) Remove SBF No. 4 from main fuse box.
3) Measure resistance of fuse.
: Is resistance less than 1Ω?
: Replace SBF No. 4.
: Go to next step 4).
4) Install SBF No. 4 to main fuse box.
5) Turn ignition switch to ON.
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8. Diagnostics for Engine Starting Failure

OBD0103A
6) Measure power supply voltage between ignition switch
connector and chassis ground.
: Connector & terminal
(B72) No. 1 (+)—Chassis ground ():
Is the voltage more than 10 V?
: Go to step8B4.
: Repair open circuit in harness between ignition
switch and SBF No. 4 connector.
8B4
CHECK TRANSMISSION TYPE.
: Is transmission type AT?
: Go to step8B5.
: Go to step8B9.
8B5
CHECK INHIBITOR SWITCH TYPE.
: Is inhibitor switch type plastic body?
: Go to step8B6.
: Go to step8B8.
B2M1279A
8B6
CHECK INHIBITOR SWITCH.
1) Turn ignition switch to OFF.
2) Place the selector lever in the“P”or“N”position.
3) Measure resistance between transmission harness
connector receptacle’s terminals.
: Connector & terminal
(T3) No. 11—No. 12:
Is the resistance less than 1Ω?
: Repair open circuit in harness between starter
motor and ignition switch connector.
: Go to step8B7.
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2-7ON-BOARD DIAGNOSTICS II SYSTEM
8. Diagnostics for Engine Starting Failure

B2M1280A
8B7
CHECK TRANSMISSION HARNESS.
1) Disconnect connector from inhibitor switch.
2) Measure resistance of harness between transmission
harness and inhibitor switch connector.
: Connector & terminal
(T3) No. 11—(T7) No. 2:
Is the resistance less than 1Ω?
: Go to next.
: Repair open circuit in harness between transmis-
sion harness and inhibitor switch connector.
B2M1281A
: Connector & terminal
(T3) No. 12—(T7) No. 1:
Is the resistance less than 1Ω?
: Go to next.
: Repair open circuit in harness between transmis-
sion harness and inhibitor switch connector.
: Is there poor contact in inhibitor switch
connector?
: Repair poor contact in inhibitor switch connector.
: Replace inhibitor switch.
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2-7ON-BOARD DIAGNOSTICS II SYSTEM
8. Diagnostics for Engine Starting Failure

B2M1279A
8B8
CHECK INHIBITOR SWITCH.
1) Turn ignition switch to OFF.
2) Place the selector lever in the“P”or“N”position.
3) Disconnect connector from transmission harness con-
nector.
4) Measure resistance between transmission harness
connector receptacle’s terminals.
: Connector & terminal
(T3) No. 11—No. 12:
Is the resistance less than 1Ω?
: Repair open circuit in harness between starter
motor and ignition switch connector.
: Replace inhibitor switch.
B2M0517A
8B9
CHECK STARTER INTERLOCK CIRCUIT.
1) Turn ignition switch to“ST”.
2) Measure voltage between clutch switch connector and
chassis ground.
: Connector & terminal

With cruise control
(B107) No. 2 (+)—Chassis ground ():

Without cruise control
(B106) No. 2 (+)—Chassis ground ():
Is the voltage more than 10 V?
: Replace starter interlock relay.
: Go to next step 3).
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8. Diagnostics for Engine Starting Failure

B2M0518A
3) Turn ignition switch to OFF.
4) Measure resistance between clutch switch connector
terminals while depressing the clutch pedal.
: Connector & terminal

With cruise control
(B107) No. 1—No. 2:

Without cruise control
(B106) No. 1—No. 2:
Is the resistance less than 10Ω?
: Repair open circuit in harness between starter
motor and ignition switch connector.
: Replace clutch switch.
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8. Diagnostics for Engine Starting Failure

C: CONTROL MODULE POWER SUPPLY AND
GROUND LINE
WIRING DIAGRAM:
B2M1049
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

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8. Diagnostics for Engine Starting Failure

G2M0444
8C1
CHECK MAIN RELAY.
1) Turn the ignition switch to OFF.
2) Remove main relay.
3) Connect battery to main relay terminals No. 1 and No.
2.
4) Measure resistance between main relay terminals.
: Terminals
No. 3—No. 5:
Is the resistance less than 10Ω?
: Go to next.
: Replace main relay.
: Terminals
No. 4—No. 6:
Is the resistance less than 10Ω?
: Go to step8C2.
: Replace main relay.
B2M0520A
8C2CHECK POWER SUPPLY CIRCUIT OF
ECM.
1) Install main relay.
2) Disconnect connectors from ECM.
3) Turn ignition switch to ON.
4) Measure power supply voltage between ECM connec-
tor terminals.
: Connector & terminal
(B84) No. 1 (+)—No. 19 ():
Is the voltage more than 10 V?
: Go to next.
: Repair open or ground short circuit in harness of
power supply circuit.
: Connector & terminal
(B84) No. 2 (+)—No. 19 ():
Is the voltage more than 10 V?
: Go to next.
: Repair open or ground short circuit in harness of
power supply circuit.
: Connector & terminal
(B84) No. 39 (+)—No. 19 ():
Is the voltage more than 10 V?
: Go to step8C3.
: Repair open or ground short circuit in harness of
power supply circuit.
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8. Diagnostics for Engine Starting Failure

B2M0521A
8C3
CHECK GROUND CIRCUIT OF ECM.
1) Turn ignition switch to OFF.
2) Measure resistance of harness connector between
ECM and chassis ground.
: Connector & terminal
(B84) No. 17—Chassis ground:
Is the resistance less than 5Ω?
: Go to next.
: Repair open circuit in harness between ECM con-
nector and engine grounding terminal.
: Connector & terminal
(B84) No. 18—Chassis ground:
Is the resistance less than 5Ω?
: Go to next.
: Repair open circuit in harness between ECM con-
nector and engine grounding terminal.
: Connector & terminal
(B84) No. 19—Chassis ground:
Is the resistance less than 5Ω?
: Go to next.
: Repair open circuit in harness between ECM con-
nector and engine grounding terminal.
: Connector & terminal
(B84) No. 20—Chassis ground:
Is the resistance less than 5Ω?
: Go to next.
: Repair open circuit in harness between ECM con-
nector and engine grounding terminal.
: Connector & terminal
(B84) No. 42—Chassis ground:
Is the resistance less than 5Ω?
: Go to next.
: Repair open circuit in harness between ECM con-
nector and engine grounding terminal.
: Connector & terminal
(B84) No. 46—Chassis ground:
Is the resistance less than 5Ω?
: Go to next.
: Repair open circuit in harness between ECM con-
nector and engine grounding terminal.
: Connector & terminal
(B84) No. 69—Chassis ground:
Is the resistance less than 5Ω?
: Go to next.
: Repair open circuit in harness between ECM con-
nector and engine grounding terminal.
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8. Diagnostics for Engine Starting Failure