EN(H6DO)(diag)-283
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step Check Yes No
1CHECK CURRENT DATA.
1) Turn the ignition switch to OFF.
2) Remove the fuel filler cap.
3) Install the fuel filler cap.
4) Turn the ignition switch to ON.
5) Read the data of fuel tank pressure sensor
signal using Subaru Select Monitor.
NOTE:•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”.
tor.>
Is the measured value 2.8 kPa
(21.0 mmHg, 0.827 inHg) or
more?
Go to step 11.Go to step 2.
2CHECK POWER SUPPLY TO FUEL TANK
PRESSURE SENSOR.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B135) No. 22 (+) — Chassis ground (–):
Is the voltage more than 4.5 V? Go to step 4.Go to step 3.
3CHECK POWER SUPPLY TO FUEL TANK
PRESSURE SENSOR.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B135) No. 22 (+) — Chassis ground (–):
Does the measured value
change by shaking ECM har-
ness and connector?
Repair poor con-
tact in ECM con-
nector.
Replace the ECM.
Engine Control
Module (ECM).>
4CHECK INPUT SIGNAL OF ECM.
Measure the voltage between ECM and chas-
sis ground.
Connector & terminal
(B135) No. 32 (+) — Chassis ground (–):
Is the voltage less than 0.2 V? Go to step 6.Go to step 5.
5CHECK INPUT SIGNAL FOR ECM (USING
SUBARU SELECT MONITOR).
Read the data of fuel tank pressure sensor sig-
nal using Subaru Select Monitor.
NOTE:
•Subaru Select Monitor
For detailed operation procedure, refer to
“READ CURRENT DATA FOR ENGINE”.
tor.>
Does the measured value
change by shaking ECM har-
ness and connector?
Repair poor con-
tact in ECM con-
nector.
Go to step 6.
6CHECK HARNESS BETWEEN ECM AND
COUPLING CONNECTOR IN REAR WIRING
HARNESS.
1) Turn the ignition switch to OFF.
2) Remove the rear seat cushion.
3) Separate rear wiring harness and fuel tank
cord.
4) Turn the ignition switch to ON.
5) Measure the voltage between rear wiring
harness connector and chassis ground.
Connector & terminal
(R15) No. 11 (+) — Chassis ground (–):
Is the voltage more than 4.5 V? Go to step 7.Repair the har-
ness and connec-
tor.
NOTE:In this case, repair
the following item:
•Open circuit
of harness be-
tween ECM and
rear wiring har-
ness connector
•Poor contact
of coupling con-
nector
EN(H6DO)(diag)-284
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
7CHECK HARNESS BETWEEN ECM AND
COUPLING CONNECTOR IN REAR WIRING
HARNESS.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Measure the resistance of harness
between ECM and rear wiring harness con-
nector.
Connector & terminal
(B135) No. 32 — (R15) No. 10:
(B135) No. 30 — (R15) No. 2:
Is the resistance less than 1
Ω?
Go to step 8.Repair the har-
ness and connec-
tor.
NOTE:In this case, repair
the following item:
•Open circuit
of harness be-
tween ECM and
rear wiring har-
ness connector
•Poor contact
of coupling con-
nector
8CHECK FUEL TANK CORD.
1) Disconnect the connector from fuel tank
pressure sensor.
2) Measure the resistance of fuel tank cord.
Connector & terminal
(R60) No. 10 — (R47) No. 2:
Is the resistance less than 1
Ω?
Go to step 9.Repair open circuit
in fuel tank cord.
9CHECK FUEL TANK CORD.
Measure the resistance of fuel tank cord.
Connector & terminal
(R60) No. 2 — (R47) No. 1:
Is the resistance less than 1
Ω?
Go to step 10.Repair open circuit
in fuel tank cord.
10 CHECK POOR CONTACT.
Check poor contact in fuel tank pressure sen-
sor connector.
Is there poor contact in fuel
tank pressure sensor connec-
tor?
Repair poor con-
tact in fuel tank
pressure sensor
connector.
Replace the fuel
tank pressure sen-
sor.
Fuel Tank Pres-
sure Sensor.>
11 CHECK HARNESS BETWEEN ECM AND
FUEL TANK PRESSURE SENSOR CONNEC-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from fuel tank
pressure sensor.
3) Turn the ignition switch to ON.
4) Read the data of fuel tank pressure sensor
signal using Subaru Select Monitor.
NOTE:•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”.
tor.>
Is the measured value 2.8 kPa
(21.0 mmHg, 0.827 inHg) or
more?
Repair short circuit
to battery in har-
ness between
ECM and fuel tank
pressure sensor
connector.
Replace the fuel
tank pressure sen-
sor.
Fuel Tank Pres-
sure Sensor.>
Step Check Yes No
EN(H6DO)(diag)-332
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
6CHECK FUEL PRESSURE
WARNING:•Place “NO FIRE” signs near the working
area.
•Be careful not to spill fuel.
Measure the fuel pressure.
WARNING:Release fuel pressure before removing the
fuel pressure gauge.
Is the measured value 338 —
348 kPa (3.4 — 3.5 kg/cm2, 49
— 50.5 psi)?
Go to step 7.Repair the follow-
ing item.
Fuel pressure is
too high:
•Clogged fuel
line or bent
hose
Fuel pressure is
too low:
•Improper fuel
pump discharge
•Clogged fuel
supply line
7CHECK ENGINE COOLANT TEMPERATURE
SENSOR.
1) Start the engine and warm-up completely.
2) Read the data of engine coolant tempera-
ture sensor signal using Subaru Select Monitor
or general scan tool.
NOTE:•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”.
tor.>
•General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Is the temperature above 60°C
(140°F)?
Go to step 8.Replace the
engine coolant
temperature sen-
sor.
Engine Coolant
Te m p e r a t u r e S e n -
sor.>
8CHECK MASS AIR FLOW AND INTAKE AIR
TEMPERATURE SENSOR.
1) Start the engine and warm-up engine until
coolant temperature is greater than 60°C
(140°F).
2) Place the shift lever in neutral position.
3) Turn the A/C switch to OFF.
4) Turn all the accessory switches to OFF.
5) Read the data of mass air flow and intake
air temperature sensor signal using Subaru
Select Monitor or general scan tool.
NOTE:•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”.
tor.>
•General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Is the measured value 3.1 —
4.3 g/s (0.4 — 0.6 lb/m)?
Go to step 9.Replace the mass
air flow and intake
air temperature
sensor.
Mass Air Flow and
Intake Air Temper-
ature Sensor.>
Step Check Yes No
EN(H6DO)(diag)-340
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
6CHECK FUEL PRESSURE
WARNING:•Place “NO FIRE” signs near the working
area.
•Be careful not to spill fuel.
Measure the fuel pressure.
WARNING:Release fuel pressure before removing the
fuel pressure gauge.
Is the measured value 338 —
348 kPa (3.4 — 3.5 kg/cm2, 49
— 50.5 psi)?
Go to step 7.Repair the follow-
ing item.
Fuel pressure is
too high:
•Clogged fuel
line or bent
hose
Fuel pressure is
too low:
•Improper fuel
pump discharge
•Clogged fuel
supply line
7CHECK ENGINE COOLANT TEMPERATURE
SENSOR.
1) Start the engine and warm-up completely.
2) Read the data of engine coolant tempera-
ture sensor signal using Subaru Select Monitor
or general scan tool.
NOTE:•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”.
tor.>
•General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Is the temperature above 60°C
(140°F)?
Go to step 8.Replace the
engine coolant
temperature sen-
sor.
Engine Coolant
Te m p e r a t u r e S e n -
sor.>
8CHECK MASS AIR FLOW AND INTAKE AIR
TEMPERATURE SENSOR.
1) Start the engine and warm-up engine until
coolant temperature is greater than 60°C
(140°F).
2) Place the shift lever in neutral position.
3) Turn the A/C switch to OFF.
4) Turn all the accessory switches to OFF.
5) Read the data of mass air flow and intake
air temperature sensor signal using Subaru
Select Monitor or general scan tool.
NOTE:•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”.
tor.>
•General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Is the measured value 3.1 —
4.3 g/s (0.4 — 0.6 lb/m)?
Go to step 9.Replace the mass
air flow and intake
air temperature
sensor.
Mass Air Flow and
Intake Air Temper-
ature Sensor.>
Step Check Yes No
EN(H6DO)(diag)-348
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
6CHECK FUEL PRESSURE
WARNING:•Place “NO FIRE” signs near the working
area.
•Be careful not to spill fuel.
Measure the fuel pressure.
WARNING:Release fuel pressure before removing the
fuel pressure gauge.
Is the measured value 338 —
348 kPa (3.4 — 3.5 kg/cm2, 49
— 50.5 psi)?
Go to step 7.Repair the follow-
ing item.
Fuel pressure is
too high:
•Clogged fuel
line or bent
hose
Fuel pressure is
too low:
•Improper fuel
pump discharge
•Clogged fuel
supply line
7CHECK ENGINE COOLANT TEMPERATURE
SENSOR.
1) Start the engine and warm-up completely.
2) Read the data of engine coolant tempera-
ture sensor signal using Subaru Select Monitor
or general scan tool.
NOTE:•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”.
tor.>
•General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Is the temperature above 60°C
(140°F)?
Go to step 8.Replace the
engine coolant
temperature sen-
sor.
Engine Coolant
Te m p e r a t u r e S e n -
sor.>
8CHECK MASS AIR FLOW AND INTAKE AIR
TEMPERATURE SENSOR.
1) Start the engine and warm-up engine until
coolant temperature is greater than 60°C
(140°F).
2) Place the shift lever in neutral position.
3) Turn the A/C switch to OFF.
4) Turn all the accessory switches to OFF.
5) Read the data of mass air flow and intake
air temperature sensor signal using Subaru
Select Monitor or general scan tool.
NOTE:•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”.
tor.>
•General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Is the measured value 3.1 —
4.3 g/s (0.4 — 0.6 lb/m)?
Go to step 9.Replace the mass
air flow and intake
air temperature
sensor.
Mass Air Flow and
Intake Air Temper-
ature Sensor.>
Step Check Yes No
EN(H6DO)(diag)-356
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
6CHECK FUEL PRESSURE
WARNING:•Place “NO FIRE” signs near the working
area.
•Be careful not to spill fuel.
Measure the fuel pressure.
WARNING:Release fuel pressure before removing the
fuel pressure gauge.
Is the measured value 338 —
348 kPa (3.4 — 3.5 kg/cm2, 49
— 50.5 psi)?
Go to step 7.Repair the follow-
ing item.
Fuel pressure is
too high:
•Clogged fuel
line or bent
hose
Fuel pressure is
too low:
•Improper fuel
pump discharge
•Clogged fuel
supply line
7CHECK ENGINE COOLANT TEMPERATURE
SENSOR.
1) Start the engine and warm-up completely.
2) Read the data of engine coolant tempera-
ture sensor signal using Subaru Select Monitor
or general scan tool.
NOTE:•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”.
tor.>
•General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Is the temperature above 60°C
(140°F)?
Go to step 8.Replace the
engine coolant
temperature sen-
sor.
Engine Coolant
Te m p e r a t u r e S e n -
sor.>
8CHECK MASS AIR FLOW AND INTAKE AIR
TEMPERATURE SENSOR.
1) Start the engine and warm-up engine until
coolant temperature is greater than 60°C
(140°F).
2) Place the shift lever in neutral position.
3) Turn the A/C switch to OFF.
4) Turn all the accessory switches to OFF.
5) Read the data of mass air flow and intake
air temperature sensor signal using Subaru
Select Monitor or general scan tool.
NOTE:•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”.
tor.>
•General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Is the measured value 3.1 —
4.3 g/s (0.4 — 0.6 lb/m)?
Go to step 9.Replace the mass
air flow and intake
air temperature
sensor.
Mass Air Flow and
Intake Air Temper-
ature Sensor.>
Step Check Yes No
EN(H6DO)(diag)-392
General Diagnostic Table
ENGINE (DIAGNOSTICS)
19.General Diagnostic Table
A: INSPECTION
1. ENGINE
NOTE:
Malfunction of parts other than those listed is also possible.
Symptom Problem parts
1. Engine stalls during idling.
1) Manifold absolute pressure sensor
2) Mass air flow and intake air temperature sensor
3) Ignition parts (*1)
4) Engine coolant temperature sensor (*2)
5) Crankshaft position sensor (*3)
6) Camshaft position sensor (*3)
7) Fuel injection parts (*4)
2. Rough idling
1) Manifold absolute pressure sensor
2) Mass air flow and intake air temperature sensor
3) Engine coolant temperature sensor (*2)
4) Ignition parts (*1)
5) Air intake system (*5)
6) Fuel injection parts (*4)
7) Electronic throttle control
8) Crankshaft position sensor (*3)
9) Camshaft position sensor (*3)
10) Oxygen sensor
11) Fuel pump and fuel pump relay
3. Engine does not return to idle.
1) Engine coolant temperature sensor
2) Electronic throttle control
3) Manifold absolute pressure sensor
4) Mass air flow and intake air temperature sensor
5) Accelerator pedal position sensor
6) Oil temperature sensor
4. Poor acceleration
1) Manifold absolute pressure sensor
2) Mass air flow and intake air temperature sensor
3) Electronic throttle control
4) Fuel injection parts (*4)
5) Fuel pump and fuel pump relay
6) Engine coolant temperature sensor (*2)
7) Crankshaft position sensor (*3)
8) Camshaft position sensor (*3)
9) A/C switch and A/C cut relay
10) Engine torque control signal circuit
11) Ignition parts (*1)
12) Accelerator pedal position sensor
13) Oil temperature sensor
5. Engine stalls, engine sags or hesitates at accel-
eration.
1) Manifold absolute pressure sensor
2) Mass air flow and intake air temperature sensor
3) Engine coolant temperature sensor (*2)
4) Crankshaft position sensor (*3)
5) Camshaft position sensor (*3)
6) Purge control solenoid valve
7) Fuel injection parts (*4)
8) Electronic throttle control
9) Fuel pump and fuel pump relay
EN(H6DO)(diag)-393
General Diagnostic Table
ENGINE (DIAGNOSTICS)
*1: Check ignition coil & ignitor assembly and spark plug.
*2: Indicate the symptom occurring only in cold temperatures.
*3: Make sure the secure installation.
*4: Check the fuel injector and fuel pressure regulator.
*5: Inspect air leak in air intake system.
6. Surging
1) Mass air flow and intake air temperature sensor
2) Manifold absolute pressure sensor
3) Engine coolant temperature sensor (*2)
4) Crankshaft position sensor (*3)
5) Camshaft position sensor (*3)
6) Fuel injection parts (*4)
7) Electronic throttle control
8) Fuel pump and fuel pump relay
7. Spark knock
1) Mass air flow and intake air temperature sensor
2) Manifold absolute pressure sensor
3) Engine coolant temperature sensor
4) Knock sensor
5) Fuel injection parts (*4)
6) Fuel pump and fuel pump relay
8. After burning in exhaust system
1) Mass air flow and intake air temperature sensor
2) Manifold absolute pressure sensor
3) Engine coolant temperature sensor (*2)
4) Fuel injection parts (*4)
5) Fuel pump and fuel pump relay
Symptom Problem parts