Subaru 2009 IMPREZA Service Manual page 1380

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of fuel temperature sensor
signal using Subaru Select Monitor.
NOTE:
For detailed operation procedures, refer to
"READ CURRENT DATA FOR ENGINE". <Ref.
to EN(H4DOTC)(diag)-34, Subaru Select Moni-
tor.>
2 CHECK POOR CONTACT.
Repair any poor contact between the ECM and
fuel temperature sensor connectors.
3 CHECK HARNESS BETWEEN ECM AND
FUEL TEMPERATURE SENSOR CONNEC-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and
fuel temperature sensor.
3) Measure the resistance of the harness
between the ECM and fuel temperature sensor
connector.
Connector & terminal
(B135) No. 17 — (R58) No. 2:
(B135) No. 30 — (R58) No. 3:
4 CHECK HARNESS BETWEEN ECM AND
FUEL TEMPERATURE SENSOR CONNEC-
TOR.
1) Connect all connectors.
2) Turn the ignition switch to ON.
3) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B135) No. 17 (+) — Chassis ground (–):
Check
Is the temperature less than
–40°C (–40°F)?
Is there poor contact of the
ECM or fuel temperature sen-
sor connectors?
Is the resistance less than 1 ? Go to step 4.
Is the voltage 5 V or more?
EN(H4DOTC)(diag)-159
ENGINE (DIAGNOSTICS)
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.
Repair any poor Go to step 3.
contact between
the ECM and fuel
temperature sen-
sor connectors.
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM and fuel tem-
perature
connector
• Poor contact of
coupling connector
Repair the short Replace the fuel
circuit to power in temperature sen-
the harness sor. <Ref. to
between the ECM EC(H4DOTC)-16,
and fuel tempera- Fuel Temperature
ture sensor con- Sensor.>
nector.
sensor