1996 SUBARU LEGACY Fuel system

OBD0191
I: DTC P0125
—INSUFFICIENT COOLANT TEMPERATURE
FOR CLOSED LOOP FUEL CONTROL
(TW
—CL)—
DTC DETECTING CONDITION:

Two consecutive trips with fault
TROUBLE SYMPTOM:

Engine would not return to idling.
10I1Check DTC P0115 on display.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

WIRING DIAGRAM:
B2M0539
159
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

WIRING DIAGRAM:

RHD Model
B2M0787
10J1CHECK FOR OTHER CAUSES AFFECT-
ING EXHAUST GAS.
: Is CO % more than 2 % after engine warm-
up?
: Check fuel system.
NOTE:

Check for use of improper fuel.

Check if engine oil or coolant level is extremely low.
: Go to step10J2.
OBD0145A
10J2
CHECK FRONT OXYGEN SENSOR DATA.
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 engine and Turn the Subaru Select Monitor and
the OBD-II general scan tool switch to ON.
4) Warm-up the engine until coolant temperature is above
70°C (160°F) and keep the engine speed at 2,000 rpm to
3,000 rpm for one minute.
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2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

10M1
CHECK DTC P0130 ON DISPLAY.
: Does the Subaru select monitor or OBD-II
general scan tool indicate DTC P0130?
: Go to step10M2.
: Go to step10M3.
10M2
CHECK FAILURE CAUSE OF P0130.
Perform the step 1 of DTC P0130.
: Is the failure cause of P0130 in the fuel sys-
tem?
: Check fuel system.
NOTE:
In this case, it is not necessary to inspect DTC P0136.
: Go to step10M3.
OBD0145A
10M3
CHECK REAR OXYGEN SENSOR DATA.
1) Turn ignition switch to OFF.
2) Connect Subaru Select Monitor or OBD-II general scan
tool to data link connector.
3) Start the engine, and turn Subaru Select Monitor or
OBD-II general scan tool switch to ON.
4) Warm-up the engine until engine coolant temperature is
above 70°C (160°F), and keep the engine speed at 2,000
rpm to 3,000 rpm for two minutes.
B2M0488
5) Read data on Subaru Select Monitor or OBD-II general
scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F13

F13: Rear oxygen sensor output signal is indicated.
: Does the value fluctuate in function mode
F13?
: Go to step10M5.
: Go to next.
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2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

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
10P1Check exhaust system.
10P2Check air intake system.
10P3Check fuel pressure.
10P4Check engine coolant temperature sensor.

10P5Check mass air flow sensor.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODE.





185
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

10P1
CHECK EXHAUST SYSTEM.
: Are there holes or loose bolts on exhaust
system?
: Repair exhaust system.
: Go to step10P2.
10P2
CHECK AIR INTAKE SYSTEM.
: Are there holes, loose bolts or disconnec-
tion of hose on air intake system?
: Repair air intake system.
: Go to step10P3.
G2M0340
10P3
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).
B2M0047
(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.
186
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

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.
: Is fuel pressure between 226 and 275 kPa
(2.3—2.8 kg/cm2,33—40 psi)?
: Go to next step 6).
: Repair the following items.
Fuel pressure too high
Clogged fuel return line or bent
hose
Fuel pressure too low
Improper fuel pump discharge

Clogged fuel supply line
6) After connecting pressure regulator vacuum hose, mea-
sure fuel pressure.
: Is fuel pressure between 157 and 206 kPa
(1.6—2.1 kg/cm2,23—30 psi)?
: Go to step10P4.
: Repair the following items.
Fuel pressure too high
Faulty pressure regulator

Clogged fuel return line or bent
hose
Fuel pressure too low
Faulty 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.
187
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

H2M1306
Q: DTC P0180
—FUEL TEMPERATURE SENSOR A CIRCUIT
MALFUNCTION (TNKT)—
DTC DETECTING CONDITION:

Immediately at fault recognition
10Q1Connect Subaru Select Monitor or the OBD-II
general scan tool, and read data.

10Q2Check harness between fuel temperature
sensor and ECM connector.
10Q3Check harness between fuel temperature
sensor and ECM connector.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

WIRING DIAGRAM:

LHD Model
B2M0916

190
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

OBD0145A
10Q1CONNECT 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.
H2M1308
5) Read data on Subaru Select Monitor or OBD-II general
scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F44

F44: Fuel temperature is indicated in“°C”and“°F”.
: Is the value greater than 150°Cor300°Fin
function mode F44?
: Go to step10Q2.
: Go to next.
H2M1308
: Is the value less than40°Cor40°Fin
function mode F44?
: Go to step10Q3.
: Repair poor contact.
NOTE:
In this case, repair the following:

Poor contact in fuel pump connector

Poor contact in ECM connector

Poor contact in coupling connector (B22, B98 (LHD)/B97
(RHD), and R57)

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