engine SUBARU LEGACY 1996 Service Repair Manual

B2M0537A
5) Turn ignition switch to OFF.
6) Disconnect connector from ECM.
7) Measure resistance of harness between ECM and pres-
sure sensor connector.
: Connector & terminal
(B84) No. 26—(B2) No. 2:
Is the resistance less than 1Ω?
: Go to next.
: Repair open circuit in harness between ECM and
pressure sensor connector.
: Connector & terminal
(B84) No. 20—(B2) No. 1:
Is the resistance less than 1Ω?
: Go to next step 8).
: Repair open circuit in harness between ECM and
pressure sensor connector.
OBD0695A
8) Measure resistance of harness between pressure sen-
sor connector and engine ground.
: Connector & terminal
(B2) No. 2—Engine ground:
Is the resistance more than 500 kΩ?
: Go to next.
: Repair short circuit in harness between ECM and
pressure sensor connector.
: Is there poor contact in pressure sensor
connector?
: Repair poor contact in pressure sensor connector.
: Replace pressure sensor.
140
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

OBD0145A
10E2
CHECK DATA FOR CONTROL.
1) Turn ignition switch to OFF.
2) Connect Subaru Select Monitor or the OBD-II general
scan tool to data link connector.
3) Turn ignition switch ON and Subaru Select Monitor or
the OBD-II general scan tool switch ON.
4) Start engine.
B2M0756
5) Read data on Subaru Select Monitor or the OBD-II gen-
eral scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F21 and F20

F21: Display shows pressure signal value sent from the
pressure sensor.

F20: Display shows pressure signal value sent from the
pressure sensor.
: Is the value more than 85 kPa in function
mode F21?
: Go to step10E3.
: Go to next.
B2M0755
: Is the value less than 32 kPa in function
mode F20?
: Go to step10E4.
: Go to next.
B2M0755
: Is the value more than 133 kPa in function
mode F20?
: Replace pressure sensor.
: Repair poor contact in pressure sensor connector,
pressure sources switching solenoid valve
connector, and ECM connector.

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
145
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

OBD0172
F: DTC P0115
—ENGINE COOLANT TEMPERATURE
SENSOR CIRCUIT MALFUNCTION (TW)—
DTC DETECTING CONDITION:

Immediately at fault recognition
TROUBLE SYMPTOM:

Hard to start

Erroneous idling

Poor driving performance
10F1Connect Subaru Select Monitor or the OBD-II
general scan tool, and read data.

10F2Check harness between engine coolant
temperature sensor and ECM connector.
10F3Check harness between engine coolant
temperature sensor and ECM connector.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

WIRING DIAGRAM:
B2M0539

147
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

OBD0145A
10F1CONNECT SUBARU SELECT MONITOR
OR THE OBD-II GENERAL SCAN TOOL,
AND READ DATA.
1) Turn ignition switch to OFF.
2) Connect Subaru Select Monitor or the OBD-II general
scan tool to data link connector.
3) Turn ignition switch to ON and Subaru Select Monitor or
OBD-II general scan tool switch to ON.
4) Start engine.
B2M0479
5) Read data on Subaru Select Monitor or OBD-II general
scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F04

F04: Water temperature is indicated in“°C”and“°F”.
: Is the value greater than 150°Cor300°Fin
function mode F04?
: Go to step10F2.
: Go to next.
B2M0479
: Is the value less than40°Cor40°Fin
function mode F04?
: Go to step10F3.
: Repair poor contact.
NOTE:
In this case, repair the following:

Poor contact in engine coolant temperature sensor

Poor contact in ECM

Poor contact in coupling connector (B21)

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
148
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

OBD0618A
10F2CHECK HARNESS BETWEEN ENGINE
COOLANT TEMPERATURE SENSOR AND
ECM CONNECTOR.
1) Turn ignition switch to OFF.
2) Remove idle air control solenoid valve by-pass air hose.
3) Disconnect connector from engine coolant temperature
sensor.
OBD0145A
4) Connect Subaru Select Monitor or the OBD-II general
scan tool to data link connector.
5) Turn ignition switch and Subaru Select Monitor or
OBD-II general scan tool switch to ON.
B2M0479
6) Read data on Subaru Select Monitor or the OBD-II gen-
eral scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F04

F04: Water temperature is indicated in“°C”and“°F”.
: Is the value less than40°Cor40°Fin
function mode F04?
: Replace engine coolant temperature sensor.
: Repair short circuit in harness between engine
coolant temperature sensor and ECM connector.

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
149
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

OBD0618A
10F3CHECK HARNESS BETWEEN ENGINE
COOLANT TEMPERATURE SENSOR AND
ECM CONNECTOR.
1) Turn ignition switch to OFF.
2) Remove idle air control solenoid valve by-pass air hose.
3) Disconnect connector from engine coolant temperature
sensor.
4) Turn ignition switch to ON.
OBD0696A
5) Measure voltage between engine coolant temperature
sensor connector and engine ground.
: Connector & terminal
(E8) No. 1 (+)—Engine ground ():
Is the voltage more than 4 V?
: Go to next step 6).
: Repair harness and connector.
NOTE:
In this case, repair the following:

Open circuit in harness between ECM and engine cool-
ant temperature sensor connector

Poor contact in engine coolant temperature sensor con-
nector

Poor contact in ECM connector

Poor contact in coupling connector (B21)
OBD0697A
6) Turn ignition switch to OFF.
7) Measure resistance of harness between engine coolant
temperature sensor connector and engine ground.
: Connector & terminal
(E8) No. 2—Engine ground:
Is the resistance less than 5Ω?
: Replace engine coolant temperature sensor.
: Repair harness and connector.
NOTE:
In this case, repair the following:

Open circuit in harness between ECM and engine cool-
ant temperature sensor connector

Poor contact in engine coolant temperature sensor con-
nector

Poor contact in ECM connector

Poor contact in coupling connector (B21)
150
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

OBD0181
G: DTC P0120
—THROTTLE POSITION SENSOR CIRCUIT
MALFUNCTION (THV)—
DTC DETECTING CONDITION:

Immediately at fault recognition
TROUBLE SYMPTOM:

Erroneous idling

Engine stalls.

Poor driving performance
10G1Connect Subaru Select Monitor or the OBD-II
general scan tool and read data.

10G2Check input signal for ECM. (Using voltage
meter and Subaru select monitor.)
10G3Check harness between ECM and throttle
position sensor connector.
10G4Check harness between throttle position
sensor and body connector.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.



151
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

OBD0145A
10G1CONNECT SUBARU SELECT MONITOR
OR THE OBD-II GENERAL SCAN TOOL,
AND READ DATA.
1) Turn ignition switch to OFF.
2) Connect Subaru Select Monitor or the OBD-II general
scan tool to data link connector.
3) Turn ignition switch to ON and Subaru Select Monitor or
OBD-II general scan tool switch to ON.
4) Start engine.
B2M0482
5) Read data on Subaru Select Monitor or OBD-II general
scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F07

F07: Throttle position sensor output signal is indicated.
: Is the value less than 0.1 V in function
mode F07?
: Go to step10G2.
: Go to next.
B2M0482
: Is the value more than 4.9 V in function
mode F07?
: Go to step10G4.
: Even if MIL lights up, the circuit has returned to a
normal condition at this time. A temporary poor
contact of the connector may be the cause.
NOTE:
In this case, repair the following:

Poor contact in throttle position sensor connector

Poor contact in ECM connector

Poor contact in coupling connector (B21)

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
153
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

OBD0700A
10G3CHECK HARNESS BETWEEN ECM AND
THROTTLE POSITION SENSOR CON-
NECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connectors from throttle position sensor.
3) Turn ignition switch to ON.
4) Measure voltage between throttle position sensor con-
nector and engine ground.
: Connector & terminal
(E13) No. 3 (+)—Engine ground ():
Is the voltage more than 4.5 V?
: Go to next step 5).
: Repair harness and connector.
NOTE:
In this case, repair the following:

Open circuit in harness between throttle position sensor
and ECM connector

Poor contact in throttle position sensor connector

Poor contact in ECM connector

Poor contact in coupling connector (B21)
B2M0543A
5) Turn ignition switch to OFF.
6) Measure resistance of harness between ECM connec-
tor and throttle position sensor connector.
: Connector & terminal
(B84) No. 6—(E13) No. 2:
Is the resistance less than 1Ω?
: Go to next step 7).
: Repair harness and connector.
NOTE:
In this case, repair the following:

Open circuit in harness between throttle position sensor
and ECM connector

Poor contact in ECM connector

Poor contact in throttle position sensor connector

Poor contact in coupling connector (B21)
155
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

OBD0702A
7) Measure resistance of harness between throttle posi-
tion sensor connector and engine ground.
: Connector & terminal
(E13) No. 2—Engine ground:
Is the resistance less than 10Ω?
: Repair short circuit in harness between throttle
position sensor and ECM connector.
: Go to next.
: Is there poor contact in throttle position
sensor connector?
: Repair poor contact in throttle position sensor
connector.
: Replace throttle position sensor.
OBD0703A
10G4CHECK HARNESS BETWEEN THROTTLE
POSITION SENSOR AND BODY CON-
NECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from throttle position sensor.
3) Measure resistance of harness between throttle posi-
tion sensor connector and engine ground.
: Connector & terminal
(E13) No. 1—Engine ground:
Is the resistance less than 5Ω?
: Go to next step 4).
: Repair open circuit in harness between throttle
position sensor and ECM connector.
OBD0704A
4) Turn ignition switch to ON.
5) Measure voltage between throttle position sensor con-
nector and engine ground.
: Connector & terminal
(E13) No. 2 (+)—Engine ground ():
Is the voltage more than 4.9 V?
: Repair short circuit in harness between throttle
position sensor and ECM connector.
: Replace throttle position sensor.
156
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code