Subaru 2009 IMPREZA Service Manual page 631

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK CURRENT DATA.
1) Turn the ignition switch to ON.
2) Read the data of fuel tank pressure sensor
signal using the Subaru Select Monitor or gen-
eral scan tool.
NOTE:
• Subaru Select Monitor
For detailed operation procedures, refer to
"READ CURRENT DATA FOR ENGINE". <Ref.
to EN(H4SO)(diag)-34, Subaru Select Moni-
tor.>
• General scan tool
For detailed operation procedures, refer to the
general scan tool operation manual.
2 CHECK FUEL TANK PRESSURE SENSOR
POWER SUPPLY.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from the fuel tank
pressure sensor.
3) Turn the ignition switch to ON.
4) Measure the voltage between the fuel tank
pressure sensor connector and chassis ground.
Connector & terminal
(R47) No. 3 (+) — Chassis ground (–):
3 CHECK HARNESS BETWEEN ECM AND
FUEL TANK PRESSURE SENSOR CONNEC-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Measure the resistance of harness between
the ECM and fuel tank pressure sensor connec-
tor.
Connector & terminal
(B135) No. 32 — (R47) No. 1:
4 CHECK HARNESS BETWEEN ECM AND
FUEL TANK PRESSURE SENSOR CONNEC-
TOR.
Measure the resistance between ECM and
chassis ground.
Connector & terminal
(B135) No. 32 — Chassis ground:
5 CHECK POOR CONTACT.
Check for poor contact between the ECM and
fuel tank pressure sensor connector.
Check
Is the measured value less than
–7.45 kPa (–55.9 mmHg,
–2.2 inHg) ?
Is the voltage 4.5 V or more?
Is the resistance less than 1 ? Go to step 4.
Is the resistance 1 M or
more?
Is there poor contact of the
ECM or fuel tank pressure sen-
sor connector?
EN(H4SO)(diag)-214
Yes No
Go to step 2. Even if DTC is
detected, the cir-
cuit has returned to
a normal condition
at this time. Repro-
duce the failure,
and then perform
the diagnosis
again.
NOTE:
In this case, tem-
porary poor con-
tact of connector
may be the cause.
Go to step 3. Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit of
harness between
ECM and fuel tank
pressure
connector
• Poor contact of
ECM connector
• Poor contact of
coupling connector
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit of
harness between
ECM and fuel tank
pressure
connector
• Poor contact of
coupling connector
Go to step 5. Repair the ground
short circuit of har-
ness between
ECM and fuel tank
pressure sensor
connector.
Replace the fuel
Repair the poor
contact of the ECM tank pressure sen-
or fuel tank pres- sor. <Ref. to
sure sensor con- EC(H4SO)-15,
nector. Fuel Tank Pres-
sure Sensor.>
sensor
sensor