SUBARU LEGACY 1997 Service Repair Manual

H2M1418B
4) Turn ignition switch to OFF.
5) Disconnect connector from ECM.
6) Turn ignition switch to ON.
7) Measure voltage between ECM connector and chassis
ground.
: Connector & terminal
(B84) No. 27 (+)—Chassis ground:
Is the voltage less than 1 V?
: Repair harness and connector.
NOTE:
In this case, repair the following:

Open circuit in harness between ECM connector and
junction A on rear wiring harness

Poor contact in coupling connector (B98)
: Repair connector.
NOTE:
In this case, repair the following:

Poor contact in fuel pump connector

Poor contact in fuel sub meter unit

Poor contact in ECM connector
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10. Diagnostic Chart with Trouble Code for LHD Vehicles

OBD0340
BB: DTC P0500
—VEHICLE SPEED SENSOR MALFUNCTION
—
DTC DETECTING CONDITION:

Immediately at fault recognition
WIRING DIAGRAM:
B2M1285
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

281
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

10BB1CHECK SPEEDOMETER OPERATION IN
COMBINATION METER.
: Does speedometer operate normally?
: Go to step10BB2.
: Check speedometer and vehicle speed sensor
.
B2M0573A
10BB2CHECK HARNESS BETWEEN ECM AND
COMBINATION METER CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from TCM.
3) Turn ignition switch to ON.
4) Measure voltage between ECM and chassis ground.
: Connector & terminal
(B84) No. 83 (+)—Chassis ground ():
Is the voltage more than 2 V?
: Repair harness and connector.
NOTE:
In this case, repair the following:

Open circuit in harness between ECM and combination
meter connector

Poor contact in ECM connector

Poor contact in combination meter connector

Poor contact in coupling connector (B37)
: Go to step10BB3.
B2M0574A
10BB3CHECK HARNESS BETWEEN ECM AND
COMBINATION METER CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from ECM.
3) Measure resistance of harness between ECM connec-
tor and chassis ground.
: Connector & terminal
(B84) No. 83—Chassis ground:
Is the resistance less than 10Ω?
: Repair ground short circuit in harness between
ECM and combination meter connector.
: Repair poor contact in ECM connector.
282
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

OBD0358
BC: DTC P0505
—IDLE CONTROL SYSTEM MALFUNCTION
—
DTC DETECTING CONDITION:

Immediately at fault recognition
TROUBLE SYMPTOM:

Erroneous idling

Engine stalls.

Engine breathing
WIRING DIAGRAM:
B2M1311
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

283
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

10BC1
CHECK AIR INTAKE SYSTEM.
1) Turn ignition switch to ON.
2) Start engine, and idle it.
: Is there a fault in air intake system?
NOTE:
Check the following items.

Loose installation of intake manifold, idle air control sole-
noid valve and throttle body

Cracks of intake manifold gasket, idle air control sole-
noid valve gasket and throttle body gasket

Loose connections and cracks of idle air control solenoid
valve by-pass hoses

Disconnections of vacuum hoses
: Repair or replace air intake system.
: Go to step10BC2.
B2M0576A
10BC2
CHECK OUTPUT SIGNAL FROM ECM.
1) Turn ignition switch to ON.
2) Measure voltage between ECM and chassis ground.
: Connector & terminal
(B84) No. 13 (+)—Chassis ground ():
Is the voltage more than 3 V?
: Go to next.
: Go to step10BC4.
: Connector & terminal
(B84) No. 14 (+)—Chassis ground ():
Is the voltage more than 3 V?
: Go to next step 3).
: Go to step10BC4.
284
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

B2M0576A
3) Turn ignition switch to OFF.
4) Disconnect connector from idle air control solenoid
valve.
5) Turn ignition switch to ON.
6) Measure voltage between ECM and chassis ground.
: Connector & terminal
(B84) No. 13 (+)—Chassis ground ():
Is the voltage more than 10 V?
: Repair battery short circuit in harness between
ECM and idle air control solenoid valve connector.
After repair, replace ECM.
: Go to next.
: Connector & terminal
(B84) No. 14 (+)—Chassis ground ():
Is the voltage more than 10 V?
: Repair battery short circuit in harness between
ECM and idle air control solenoid valve connector.
After repair, replace ECM.
: Go to next.
: Is there poor contact in ECM connector?
: Repair poor contact in ECM connector.
: Go to step10BC3.
285
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

B2M0769
10BC3CHECK IDLE AIR CONTROL SOLENOID
VA LV E .
1) Turn ignition switch to OFF.
2) Measure resistance between idle air control solenoid
valve connector terminals.
: Terminals
No. 1—No. 2:
Is the resistance more than 20Ω?
: Replace idle air control solenoid valve.
: Go to next.
: Terminals
No. 2—No. 3:
Is the resistance more than 20Ω?
: Replace idle air control solenoid valve.
: Go to next.
: Terminals
No. 1—No. 2:
Is the resistance less than 5Ω?
: Replace idle air control solenoid valve and ECM.
: Go to next.
: Terminals
No. 2—No. 3:
Is the resistance less than 5Ω?
: Replace idle air control solenoid valve and ECM.
: Go to next step 3).
B2M0577
3) Remove idle air control solenoid valve. [W12A0].>
4) Check operation of idle air control solenoid valve.
: Is idle air control solenoid valve fully
opened when applying the battery to termi-
nals No. 2 (+) and No. 1 ()?
: Go to next.
: Clean idle air control solenoid valve. [W12B0].>
OBD0684
: Is idle air control solenoid valve fully closed
when applying the battery to terminals No. 2
(+) and No. 3 ()?
: Go to step10BC4.
: Clean idle air control solenoid valve. [W12B0].>
286
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

B2M0578A
10BC4CHECK POWER SUPPLY TO IDLE AIR
CONTROL SOLENOID VALVE.
1) Turn ignition switch to OFF.
2) Disconnect connector from idle air control solenoid
valve.
3) Turn ignition switch to ON.
4) Measure voltage between idle air control solenoid valve
and engine ground.
: Connector & terminal
(E7) No. 2 (+)—Engine ground ():
Is the voltage more than 10 V?
: Go to step10BC5.
: Repair open circuit in harness between idle air
control solenoid valve and main relay connector.
B2M0579A
10BC5CHECK HARNESS BETWEEN ECM AND
IDLE AIR CONTROL SOLENOID VALVE
CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from ECM.
3) Measure resistance of harness between ECM and idle
air control solenoid valve connector.
: Connector & terminal
(B84) No. 14—(E7) No. 1:
Is the resistance less than 1Ω?
: Go to next.
: Repair open circuit in harness between ECM and
idle air control solenoid valve connector.
: Connector & terminal
(B84) No. 13—(E7) No. 3:
Is the resistance less than 1Ω?
: Go to next step 4).
: Repair open circuit in harness between ECM and
idle air control solenoid valve connector.
B2M0580A
4) Measure resistance of harness between ECM and
chassis ground.
: Connector & terminal
(B84) No. 13—Chassis ground:
Is the resistance less than 10Ω?
: Repair ground short circuit in harness between
ECM and idle air control solenoid valve connector.
: Go to next.
287
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

: Connector & terminal
(B84) No. 14—Chassis ground:
Is the resistance less than 10Ω?
: Repair ground short circuit in harness between
ECM and idle air control solenoid valve connector.
: Go to next.
: Is there poor contact in idle air control sole-
noid valve connector?
: Repair poor contact in idle air control solenoid
valve connector.
: Contact with SOA service.
NOTE:
Inspection by DTM is required, because probable cause is
deterioration of multiple parts.
288
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

B2M1104
BD: DTC P0506
—IDLE CONTROL SYSTEM RPM LOWER
THAN EXPECTED—
DTC DETECTING CONDITION:

Two consecutive driving cycles with fault
TROUBLE SYMPTOM:

Engine is difficult to start.

Engine does not start.

Erroneous idling

Engine stalls.
WIRING DIAGRAM:
B2M1311
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

289
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles