SUBARU LEGACY 1995 Service Repair Manual

2
CHECK AIR INTAKE SYSTEM.
1) Turn ignition switch to ON.
2) Start engine, and idle it.
:
Check intake manifold, idle air control
solenoid valve and throttle body for loose
installation and gasket for cracks.

Check by-pass hose for loose connection
and cracks.

Check vacuum hoses for disconnections.
: Repair air suction and leaks.
: Replace idle air control solenoid valve.
265
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

AK: DTC P0600
—SERIAL COMMUNICATION LINK
MALFUNCTION—
DESCRIPTION:
The serial communication link circuit monitors data com-
munication between scan tool and ECM.
DTC DETECTING CONDITION:

Two consecutive trips with fault
1.Check harness.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES. [T3D0] and [T3E0].>
WIRING DIAGRAM:

LHD model
B2M0627
266
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

WIRING DIAGRAM:

RHD model
B2M0458
OBD0722A
1
CHECK HARNESS.
1) Turn ignition switch to OFF.
2) Disconnect connector from ECM.
3) Measure resistance of harness connector between
ECM and data link connector (for OBD-II general scan
tool).
: Connector & terminal
(B84) No. 41—(B40) No. 10 / 10Ω, or less
: Repair open circuit of harness between ECM con-
nector and data link connector.
: Go to the next step.
267
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0723A
4) Measure resistance between ECM harness connector
and body.
: Connector & terminal
(B84) No. 41—Body / 10Ω, or less
: Repair short circuit of harness between ECM con-
nector and data link connector.
: Repair poor contact in ECM connector and data
link connector.
OBD0376
AL: DTC P0601
—INTERNAL CONTROL MODULE MEMORY
CHECK SUM ERROR (RAM)—
DESCRIPTION:
The RAM monitors the ECM microcomputer operation.
DTC DETECTING CONDITION:

Two consecutive trips with fault
TROUBLE SYMPTOM:

Engine does not start.

Engine stalls.
1.Check DTC P0601 on display.
Ye s
Replace ECM.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES. [T3D0] and [T3E0].>

268
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

WIRING DIAGRAM:

LHD model
OBD0377
WIRING DIAGRAM:

RHD model
B2M0459
269
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

1
CHECK DTC P0601 ON DISPLAY.
: Check that DTC P0601 is indicated on
Subaru Select Monitor or OBD-II general
scan tool.
: Replace ECM.
270
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0586
AM: DTC P0703
—BRAKE SWITCH INPUT MALFUNCTION
(BRK)—
DTC DETECTING CONDITION:

Two consecutive trips with fault
1.Check operation of brake light.
2.Check harness connector between TCM and
brake light switch.
3.Check input signal for TCM.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES. [T3D0] and [T3E0].>
WIRING DIAGRAM:
OBD0587


271
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

1
CHECK OPERATION OF BRAKE LIGHT.
: Depress brake pedal to ensure that brake
light comes on.
: Go to step 2.
: Repair or replace brake light circuit.
OBD0589A
2CHECK HARNESS CONNECTOR BETWEEN
TCM AND BRAKE LIGHT SWITCH.
1) Disconnect connectors from TCM and brake light
switch.
2) Measure resistance of harness connector between
TCM and brake light switch.
: Connector & terminal
(B56) No. 7—(B64) No. 2 / 1Ω, or less
(B56) No. 7—(B65) No. 3 / 1Ω, or less
(With cruise control)
(B56) No. 7—(B67) No. 2 / 1Ω, or less
(With traction control)
: Go to next step.
: Repair or replace harness and connector.
NOTE:
In this case, there is a possibility of open circuit in the har-
ness between the brake light switch connector and TCM
connector.
OBD0590A
3) Measure resistance of harness connector between
TCM and body.
: Connector & terminal
(B56) No. 7—Body / 1 MΩ, or more
: Go to step 3.
: Repair short circuit of harness between TCM con-
nector and body.
272
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0588A
3
CHECK INPUT SIGNAL FOR TCM.
1) Connect connectors to TCM and brake light switch.
2) Measure voltage between TCM and body.
: Connector & terminal
(B56) No. 7—Body / 1 V, or less [When
release the brake pedal.]
(B56) No. 7—Body / 10 V, or more [When
depress the brake pedal.]
: Go to next.
: Adjust or replace brake light switch.
: Is there poor contact in TCM connector?
: Repair poor contact in TCM connector.
: Replace TCM with a new one.
273
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0591
AN: DTC P0705
—TRANSMISSION RANGE SENSOR CIRCUIT
MALFUNCTION (RNG)—
OBD0592A
DESCRIPTION:

The inhibitor switch assures safety when starting the
engine. This switch is mounted on the right side of the
transmission case, and is operated by the range selector
lever.

When the selector lever is set to“P”or“N”, the electri-
cal circuit is connected in the inhibitor switch and the starter
circuit is energized for cracking the engine.

When the selector lever is set to“R”,“D”,“3”,“2”,or“1”
range, the electrical circuit is disconnected in the inhibitor
switch. Hence engine cranking is disabled. In the“R”
range, the back-up light circuit is completed in the switch,
and the back-up lights come on.
DTC DETECTING CONDITION:

Two consecutive trips with fault
TROUBLE SYMPTOM:

Starter does not rotate when selector lever is in“P”or
“N”range.

Starter rotates when selector lever is in“R”,“D”,“3”,“2”
or“1”range.

Engine brake is not effected when selector lever is in“3”
range.

Shift characteristics are erroneous.
274
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code