EN(H4DOTC)(diag)-136
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
Check
Yes
No
1
CHECK CURRENT DATA.
1) Start the engine.
2) Read the value of «Intake Air Temp.» using
the Subaru Select Monitor or a general scan
tool.
NOTE:
• Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H4DOTC)(diag)-40, Subaru Select Moni-
tor.>
• General scan tool
For detailed operation procedures, refer to the
general scan tool operation manual.
Is the value of «Intake Air Temp.»
less than –40°C (–40°F)?
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,
temporary open or
short circuit of har-
ness may be the
cause.
2
CHECK FOR POOR CONTACT.
Check for poor contact of ECM and mass air
flow and intake air temperature sensor connec-
tor.
Is there poor contact of ECM or
mass air flow and intake air
temperature sensor connector?
Repair the poor
contact of ECM or
mass air flow and
intake air tempera-
ture sensor con-
nector.
Go to step
3.
3
CHECK HARNESS BETWEEN ECM AND
MASS AIR FLOW AND INTAKE AIR TEM-
PERATURE SENSOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM and
the mass air flow and intake air temperature
sensor.
3) Measure the resistance of harness between
ECM connector and the mass air flow and
intake air temperature sensor connector.
Connector & terminal
(B136) No. 31 — (B3) No. 1:
(B135) No. 30 — (B3) No. 2:
Is the resistance less than 1 Ω? Go to step
4.
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM
connector
and the mass air
flow and intake air
temperature sen-
sor connector
• Poor contact of
joint connector
4
CHECK HARNESS BETWEEN ECM AND
MASS AIR FLOW AND INTAKE AIR TEM-
PERATURE SENSOR CONNECTOR.
1) Connect all connectors.
2) Turn the ignition switch to ON.
3) Measure the voltage between ECM connec-
tor and chassis ground.
Connector & terminal
(B136) No. 31 (+) — Chassis ground (–):
Is the voltage 5 V or more?
Repair the short
circuit of harness
to power supply
between ECM con-
nector and the
mass air flow and
intake air tempera-
ture sensor con-
nector.
Replace the mass
air flow and intake
air temperature
sensor. <Ref. to
FU(STI)-42, Mass
Air Flow and Intake
Air Temperature
Sensor.> <Ref. to
FU(w/o STI)-42,
Mass Air Flow and
Intake Air Temper-
ature Sensor.>