1995 SUBARU LEGACY ecu

OBD0370
AI: DTC P0506
—IDLE CONTROL SYSTEM RPM LOWER
THAN EXPECTED (ISC
—L)—
DESCRIPTION:
Refer to“AH: DTC P0505—IDLE CONTROL SYSTEM
MALFUNCTION—[T11AH0]”.
DTC DETECTING CONDITION:

Two consecutive trips with fault
TROUBLE SYMPTOM:

Engine is difficult to start.

Engine does not start.

Erroneous idling

Engine stalls.
1.Check DTC P0505 on display.
No
Ye s

Inspect DTC P0505 using“11. Diagnostics Chart
with Trouble Code [T1100]”.

In this case, it is unnecessary to inspect DTC
P0506.
2.Check air intake system.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES. [T3D0] and [T3E0].>

262
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0371
AJ: DTC P0507
—IDLE CONTROL SYSTEM RPM HIGHER
THAN EXPECTED (ISC
—H)—
DESCRIPTION:
Refer to“AH: DTC P0505—IDLE CONTROL SYSTEM
MALFUNCTION—[T11AH0]”.
DTC DETECTING CONDITION:

Two consecutive trips with fault
TROUBLE SYMPTOM:

Engine keeps running at higher revolution than specified
idling revolution.
1.Check DTC P0505 on display.
No
Ye s

Inspect DTC P0505 using“11. Diagnostics Chart
with Trouble Code [T1100]”.

In this case, it is unnecessary to inspect DTC
P0507.
2.Check air intake system.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES. [T3D0] and [T3E0].>

264
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

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

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

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

OBD0380
AO: DTC P0710
—TRANSMISSION FLUID TEMPERATURE
SENSOR CIRCUIT MALFUNCTION (ATF)—
H2M1145
DESCRIPTION:
This sensor is mounted to the control valve in the transmis-
sion. It detects temperature change as an analog electrical
signal. The output characteristics of the sensor are shown
in the illustration.
DTC DETECTING CONDITION:

Two consecutive trips with fault
TROUBLE SYMPTOM:

No shift up to 4th speed (after engine warm-up)

No lock-up occurs. (after engine warm-up)

Excessive shift shock
279
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0392
AP: DTC P0720
—OUTPUT SPEED SENSOR (VEHICLE
SPEED SENSOR 1) CIRCUIT MALFUNCTION
(ATVSP)—
OBD0393A
DESCRIPTION:
[FWD model]

The vehicle speed sensor 1 is mounted to the transmis-
sion case (at the rear side of the case). The sensor outputs
a pulse signal which is transmission to the TCM where it is
converted to vehicle speed.

Vehicle speed sensor 1 on FWD model detects front-
wheel speed.
OBD0394A
[AWD]

The vehicle speed sensor 1 (output shaft rotation sen-
sor) is mounted to the extension case (from the outside of
the case). The sensor outputs a pulse signal which is trans-
mitted to the TCM where it is converted to vehicle speed.

The transfer clutch drum is connected directly to the rear
wheel driving propeller shaft. Vehicle speed sensor 1 on
the AWD model defects rear-wheel speed.
DTC DETECTING CONDITION:

Two consecutive trips with fault
TROUBLE SYMPTOM:

No shift or excessive tight corner“braking”
281
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code