SUBARU LEGACY 1996 Service Repair Manual

B2M0769
10AN3CHECK 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. <Ref. to 2-7
[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. <Ref. to 2-7
[W12B0].>
OBD0684
: Is idle air control solenoid valve fully closed
when applying the battery to terminals No. 2
(+) and No. 3 ()?
: Go to step10AN4.
: Clean idle air control solenoid valve. <Ref. to 2-7
[W12B0].>
273
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

B2M0578A
10AN4CHECK 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 step10AN5.
: Repair open circuit in harness between idle air
control solenoid valve and main relay connector.
B2M0579A
10AN5CHECK 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 short circuit in harness between ECM and
idle air control solenoid valve connector.
: Go to next.
274
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

: Connector & terminal
(B84) No. 14—Chassis ground:
Is the resistance less than 10Ω?
: Repair 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.
275
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

OBD0370
AO: DTC P0506
—IDLE CONTROL SYSTEM RPM LOWER
THAN EXPECTED (ISC
—L)—
DTC DETECTING CONDITION:

Two consecutive trips with fault
TROUBLE SYMPTOM:

Engine is difficult to start.

Engine does not start.

Erroneous idling

Engine stalls.
10AO1Check DTC P0505 on display.
10AO2Check air intake system.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.
<Ref. to 2-7 [T3D0] and [T3E0].>
10AO1
CHECK DTC P0505 ON DISPLAY.
: Does the Subaru select monitor or OBD-II
general scan tool indicate DTC P0505?
: Inspect DTC P0505 using“10. Diagnostics Chart
with Trouble Code 2-7 [T1000]”.
NOTE:
In this case, it is not necessary to inspect DTC P0506.
: Go to step10AO2.
10AO2
CHECK AIR INTAKE SYSTEM.
1) Turn ignition switch to ON.
2) Start engine, and idle it.
: Is clogging the by-pass line between by-
pass hose and intake duct?
: Repair the by-pass line.
: Replace idle air control solenoid valve.

276
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

OBD0371
AP: DTC P0507
—IDLE CONTROL SYSTEM RPM HIGHER
THAN EXPECTED (ISC
—H)—
DTC DETECTING CONDITION:

Two consecutive trips with fault
TROUBLE SYMPTOM:

Engine keeps running at higher revolution than specified
idling revolution.
10AP1Check DTC P0505 on display.
10AP2Check air intake system.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.
<Ref. to 2-7 [T3D0] and [T3E0].>
10AP1
CHECK DTC P0505 ON DISPLAY.
: Does the Subaru select monitor or OBD-II
general scan tool indicate DTC P0505?
: Inspect DTC P0505 using“10. Diagnostics Chart
with Trouble Code 2-7 [T1000]”.
NOTE:
In this case, it is not necessary to inspect DTC P0507.
: Go to step10AP2.
10AP2
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 air suction and leaks.
: Replace idle air control solenoid valve.

277
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

AQ: DTC P0600
—SERIAL COMMUNICATION LINK
MALFUNCTION—
DTC DETECTING CONDITION:

Two consecutive trips with fault
10AQ1Check harness between ECM and data link
connector.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.
<Ref. to 2-7 [T3D0] and [T3E0].>
WIRING DIAGRAM:

LHD Model
B2M0581
278
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

WIRING DIAGRAM:

RHD Model
B2M0797
279
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

B2M0582A
10AQ1CHECK HARNESS BETWEEN ECM AND
DATA LINK CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from ECM.
3) Measure resistance of harness between ECM and data
link connector (for Subaru Select Monitor & OBD-II general
scan tool).
: Connector & terminal
(B84) No. 93—(B40) No. 10:
Is the resistance less than 1Ω?
: Go to next step 4).
: Repair open circuit in harness between ECM and
data link connector.
B2M0583A
4) Measure resistance of harness between ECM and
chassis ground.
: Connector & terminal
(B84) No. 93—Chassis ground:
Is the resistance less than 10Ω?
: Repair short circuit in harness between ECM and
data link connector.
: Repair poor contact in ECM connector and data
link connector.
280
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

OBD0376
AR: DTC P0601
—INTERNAL CONTROL MODULE MEMORY
CHECK SUM ERROR (RAM)—
DTC DETECTING CONDITION:

Two consecutive trips with fault
TROUBLE SYMPTOM:

Engine does not start.

Engine stalls.
10AR1Check DTC P0601 on display.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.
<Ref. to 2-7 [T3D0] and [T3E0].>
WIRING DIAGRAM:

LHD Model
B2M0519
281
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

WIRING DIAGRAM:

RHD Model
B2M0798
10AR1
CHECK DTC P0601 ON DISPLAY.
: Does the Subaru select monitor or OBD-II
general scan tool indicate DTC P0601?
: Replace ECM.
282
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code