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WIRING DIAGRAM:
RHD model
B2M0463
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OBD0145A
1CONNECT 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.
OBD0708
5) Read data on Subaru Select Monitor or OBD-II general
scan tool.
Subaru Select Monitor
Designate mode using function key.
Function mode: F30
F30: Rear oxygen sensor heater current is indicated.
: Is the reading of F30 0.2 A, or more?
: Go to step 2.
: Repair connector.
NOTE:
In this case, poor contact of rear oxygen sensor connector
and ECM connector can be the possible cause.
OBD-II scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
OBD0709A
2CHECK OUTPUT SIGNAL FROM ECM. (USING
VOLTAGE METER.)
1) Start and idle the engine.
2) Measure voltage between ECM and body.
: Connector & terminal
(B84) No. 43—Body/1.0 V, or less
: Go to step 3.
: Go to next.
: Is the voltage less than 1.0 V while shaking
harness and connector of ECM?
: Repair poor contact in ECM connector.
: Go to next step.
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OBD0709A
3) Disconnect connector from rear oxygen sensor.
4) Measure voltage between ECM and body.
: Connector & terminal
(B84) No. 43—Body/1.0 V, or less
: Replace ECM.
: Repair short circuit of harness between ECM and
rear oxygen sensor connector. After repair short
circuit of harness, replace ECM.
OBD0710A
3CHECK POWER SUPPLY TO REAR OXYGEN
SENSOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from rear oxygen sensor.
3) Turn ignition switch to ON.
4) Measure voltage between rear oxygen sensor connec-
tor and body.
: Connector & terminal
(T6) No. 2—Body/10 V, or more
: Go to step 4.
: Repair power supply line.
NOTE:
In this case, repair poor contact in connector or open cir-
cuit of harness between main relay and rear oxygen sen-
sor.
OBD0706
4
CHECK REAR OXYGEN SENSOR.
1) Turn ignition switch to OFF.
2) Measure resistance between rear oxygen sensor con-
nector terminals.
: Terminals
No. 1—No. 2/30Ω, or less
: Repair harness and connector.
NOTE:
In this case, repair the following.
1Open circuit of harness between rear oxygen sensor
connector and ECM connector
2Poor contact in rear oxygen sensor connector
3Poor contact in ECM connector
4Poor contact in rear oxygen sensor connecting harness
connector
: Replace rear oxygen sensor.
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OBD0240
P: DTC P0170
—FUEL TRIM MALFUNCTION (FUEL)—
DTC DETECTING CONDITION:
Two consecutive trips with fault
TROUBLE SYMPTOM:
Erroneous idling
Engine stalls.
Poor driving performance
1.Check exhaust system.
2.Check air intake system.
3.Check fuel pressure.
4.Check engine coolant temperature sensor.
5.Check mass air flow sensor.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODE.
[T3D0] and [T3E0].>
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1
CHECK EXHAUST SYSTEM.
: Are there holes or loose bolts on exhaust
system?
: Repair exhaust system.
: Go to step 2.
2
CHECK AIR INTAKE SYSTEM.
: Are there holes, loose bolts or disconnec-
tion of hose on air intake system?
: Repair air intake system.
: Go to step 3.
B2M0047
3
CHECK FUEL PRESSURE.
1) Release fuel pressure.
(1) Remove fuel pump access hole lid located on the
right rear of trunk compartment floor (Sedan) or lug-
gage compartment floor (Wagon).
(2) Disconnect connector from fuel tank.
(3) Start the engine, and run it until it stalls.
(4) After stopping the engine, crank the engine for 5 to
7 seconds to reduce fuel pressure.
(5) Turn ignition switch to OFF.
B2M0047
2) Connect connector to fuel tank.
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OBD0711
3) Disconnect fuel delivery hose from fuel filter, and con-
nect fuel pressure gauge.
G2M0348
4) Start the engine and idle while gear position is neutral.
5) Measure fuel pressure while disconnecting pressure
regulator vacuum hose from intake manifold.
: Fuel pressure:
226—275 kPa (2.3—2.8 kg/cm2,
33—40 psi)
: Go to next step.
: Repair the following items.
Fuel pressure too highClogged fuel return line or bent
hose
Fuel pressure too lowImproper fuel pump discharge
Clogged fuel supply line
6) After connecting pressure regulator vacuum hose, mea-
sure fuel pressure.
: Fuel pressure:
157—206 kPa (1.6—2.1 kg/cm2,
23—30 psi)
: Go to step 4.
: Repair the following items.
Fuel pressure too highFaulty pressure regulator
Clogged fuel return line or bent
hose
Fuel pressure too lowFaulty pressure regulator
Improper fuel pump discharge
Clogged fuel supply line
WARNING:
Before removing fuel pressure gauge, release fuel
pressure.
NOTE:
If fuel pressure does not increase, squeeze fuel return
hose 2 to 3 times, then measure fuel pressure again.
If out of specification as measured at step 6), check or
replace pressure regulator and pressure regulator vacuum
hose.
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4CHECK ENGINE COOLANT TEMPERATURE
SENSOR.
< REF. TO“F: DTC P0115 [T11F0].”>
1) Turn ignition switch to OFF.
OBD0145A
2) Connect the Subaru Select Monitor or the OBD-II gen-
eral scan tool to data link connector.
3) Start the engine and warm-up completely.
OBD0176
OBD0177
4) Read data on Subaru Select Monitor or the OBD-II gen-
eral scan tool.
Subaru Select Monitor
Designate mode using function key.
Function mode: F05 or F06
F05: Water temperature is indicated in“°F”.
F06: Water temperature is indicated in“°C”.
: Is temperature indicated on Subaru Select
Monitor (F05) greater than 140°F?
Is temperature indicated on Subaru Select
Monitor (F06) greater than 60°C?
: Go to step 5.
: Replace engine coolant temperature sensor.
OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
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OBD0145A
5
CHECK MASS AIR FLOW SENSOR.
1) Turn ignition switch to OFF.
2) Connect the Subaru Select Monitor or the OBD-II gen-
eral scan tool to data link connector.
3) Start the engine and warm-up engine until coolant tem-
perature is greater than 60°C (140°F).
OBD0616
4) Read data on Subaru Select Monitor or OBD-II general
scan tool.
Subaru Select Monitor
Designate mode using function key.
Function mode: F47
F47: Mass air flow is shown on display.
: Is the voltage within the specifications
shown in the following table?
Engine speed Specified value
Idling 1.9—3.6 (g/sec)
2,500 rpm 7.0—14.8 (g/sec)
: Replace mass air flow sensor.
: Contact with SOA service.
Note: Inspection by DTM is required.
Probable cause: Deterioration of plural parts
OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
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11. Diagnostics Chart with Trouble Code