SUBARU LEGACY 1997 Service Repair Manual

B2M1098
AU: DTC P0446
—EVAPORATIVE EMISSION CONTROL
SYSTEM VENT CONTROL LOW INPUT—
DTC DETECTING CONDITION:

Two consecutive driving cycles with fault
WIRING DIAGRAM:
B2M1155
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.
<Ref. to 2-7 [T3D0] and [T3E0].>
470
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11. Diagnostic Chart with Trouble Code for RHD Vehicles

H2M1370B
11AU1
CHECK OUTPUT SIGNAL FROM ECM.
1) Turn ignition switch to ON.
2) Measure voltage between ECM and chassis ground.
: Connector & terminal
(B84) No. 35 (+)—Chassis ground ():
Is the voltage more than 10 V?
: Go to next.
: Go to step11AU2.
: Is there poor contact in ECM connector?
: Repair poor contact in ECM connector.
: Even if MIL lights up, the circuit has returned to a
normal condition at this time. (However, the pos-
sibility of poor contact still remains.)
NOTE:
In this case, repair the following:

Poor contact in vent control solenoid valve connector

Poor contact in ECM connector

Poor contact in coupling connectors (B97 and R57)
H2M1239C
11AU2CHECK HARNESS BETWEEN VENT
CONTROL SOLENOID VALVE AND ECM
CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connectors from vent control solenoid valve
and ECM.
3) Measure resistance of harness between vent control
solenoid valve connector and chassis ground.
: Connector & terminal
(R69) No. 2—Chassis ground:
Is the resistance less than 10Ω?
: Repair ground short circuit in harness between
ECM and vent control solenoid valve connector.
: Go to next step 4).
H2M1371B
4) Measure resistance of harness between ECM and vent
control solenoid valve connector.
: Connector & terminal
(B84) No. 35—(R69) No. 2:
Is the voltage less than 1Ω?
: Go to step11AU3.
: Repair harness and connector.
471
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostic Chart with Trouble Code for RHD Vehicles

NOTE:
In this case, repair the following:

Open circuit in harness between ECM and vent control
solenoid valve connector

Poor contact in coupling connectors (B97 and R57)
H2M1238A
11AU3CHECK VENT CONTROL SOLENOID
VA LV E .
Measure resistance between vent control solenoid valve
terminals.
: Terminals
No. 1—No. 2:
Is the resistance between 10 and 100Ω?
: Go to step11AU4.
: Replace vent control solenoid valve.
H2M1241C
11AU4CHECK POWER SUPPLY TO VENT CON-
TROL SOLENOID VALVE.
1) Turn ignition switch to ON.
2) Measure voltage between vent control solenoid valve
and chassis ground.
: Connector & terminal
(R69) No. 1 (+)—Chassis ground ():
Is the voltage more than 10 V?
: Go to next.
: Repair harness and connector.
NOTE:
In this case, repair the following:

Open circuit in harness between main relay and vent
control solenoid valve

Poor contact in coupling connectors (B97 and R57)

Poor contact in main relay connector
: Is there poor contact in vent control sole-
noid valve connector?
: Repair poor contact in vent control solenoid valve
connector.
: Contact with SOA service.
NOTE:
Inspection by DTM is required, because probable cause is
deterioration of multiple parts.
472
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostic Chart with Trouble Code for RHD Vehicles

H2M1377
AV: DTC P0451
—EVAPORATIVE EMISSION CONTROL
SYSTEM PRESSURE SENSOR
RANGE/PERFORMANCE PROBLEM—
WIRING DIAGRAM:
B2M1019
NOTE:
Check fuel tank pressure control system.
<Ref. to 2-7 [T10AV0].>
473
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostic Chart with Trouble Code for RHD Vehicles

B2M1099
AW: DTC P0452
—EVAPORATIVE EMISSION CONTROL
SYSTEM PRESSURE SENSOR LOW INPUT
—
DTC DETECTING CONDITION:

Immediately at fault recognition
WIRING DIAGRAM:
B2M1019
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.
<Ref. to 2-7 [T3D0] and [T3E0].>
474
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostic Chart with Trouble Code for RHD Vehicles

B2M1016A
11 AW 1CONNECT SUBARU SELECT MONITOR
OR THE OBD-II GENERAL SCAN TOOL,
AND READ DATA.
1) Turn ignition switch to OFF.
2) Remove fuel filler cap.
3) Install fuel filler cap.
4) Connect Subaru Select Monitor or the OBD-II general
scan tool to data link connector.
5) Turn ignition switch to ON and Subaru Select Monitor or
the OBD-II general scan tool switch to ON.
H2M1326
6) Read the data on Subaru Select Monitor or the OBD-II
general scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F43

F43: Display shows pressure signal value sent from fuel
tank pressure sensor.
: Is the value less than2.8 kPa in function
mode F43?
: Go to step11 AW 2.
: Even if MIL lights up, the circuit has returned to a
normal condition at this time.

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
B2M0535A
11 AW 2CHECK INPUT SIGNAL FOR ECM.
(USING VOLTAGE METER AND SUBARU
SELECT MONITOR.)
1) Measure voltage between ECM connector and chassis
ground.
: Connector & terminal
(B84) No. 21 (+)—Chassis ground ():
Is the voltage more than 4.5 V?
: Go to next step 2).
: Go to next.
475
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostic Chart with Trouble Code for RHD Vehicles

B2M0535A
: Does the voltage change more than 4.5 V by
shaking harness and connector of ECM
while monitoring the value with voltage
meter?
: Repair poor contact in ECM connector.
: Contact with SOA service.
NOTE:
Inspection by DTM is required, because probable cause is
deterioration of multiple parts.
H2M1374B
2) Measure voltage between ECM and chassis ground.
: Connector & terminal
(B84) No. 4 (+)—Chassis ground ():
Is the voltage less than 0.2 V?
: Go to step11 AW 3.
: Go to next step 3).
H2M1326
3) Read data on Subaru Select Monitor.

Subaru Select Monitor
Designate mode using function key.
Function mode: F43

F43: Display shows pressure signal value sent from fuel
tank pressure sensor.
: Does the value change more than2.8 kPa
by shaking harness and connector of ECM
while monitoring the value with Subaru
select monitor?
: Repair poor contact in ECM connector.
: Go to step11 AW 3.
B2M0927
11 AW 3CHECK HARNESS BETWEEN ECM AND
FUEL TANK PRESSURE SENSOR CON-
NECTOR.
1) Turn ignition switch to OFF.
2) Detach right side rear quarter trim panel.
3) Remove right side rear quarter trim pocket.
4) Detach right side rear quarter insulator.
476
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostic Chart with Trouble Code for RHD Vehicles

H2M1255B
5) Disconnect connector from fuel tank pressure sensor.
6) Turn ignition switch to ON.
7) Measure voltage between fuel tank pressure sensor
connector and chassis ground.
: Connector & terminal
(R47) No. 3 (+)—Chassis ground ():
Is the voltage more than 4.5 V?
: Go to next step 8).
: Repair harness and connector.
NOTE:
In this case, repair the following:

Open circuit in harness between ECM and fuel tank
pressure sensor connector

Poor contact in coupling connector (B97)
H2M1376B
8) Turn ignition switch to OFF.
9) Disconnect connector from ECM.
10) Measure resistance of harness between ECM and
pressure sensor connector.
: Connector & terminal
(B84) No. 20—(R47) No. 1:
Is the resistance less than 1Ω?
: Go to next step 11).
: Repair harness and connector.
NOTE:
In this case, repair the following:

Open circuit in harness between ECM and fuel tank
pressure sensor connector

Poor contact in coupling connector (B97)
477
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostic Chart with Trouble Code for RHD Vehicles

H2M1257B
11) Measure resistance of harness between fuel tank
pressure sensor connector and chassis ground.
: Connector & terminal
(R47) No. 1—Chassis ground:
Is the resistance more than 500 kΩ?
: Go to next.
: Repair ground short circuit in harness between
ECM and fuel tank pressure sensor connector.
: Is there poor contact in fuel tank pressure
sensor connector?
: Repair poor contact in fuel tank pressure sensor
connector.
: Replace fuel tank pressure sensor.
478
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostic Chart with Trouble Code for RHD Vehicles

B2M1100
AX: DTC P0453
—EVAPORATIVE EMISSION CONTROL
SYSTEM PRESSURE SENSOR HIGH INPUT
—
DTC DETECTING CONDITION:

Immediately at fault recognition
WIRING DIAGRAM:
B2M1019
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.
<Ref. to 2-7 [T3D0] and [T3E0].>
479
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostic Chart with Trouble Code for RHD Vehicles