Subaru Legacy 2004 Service Manual page 863

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK OPTION CODE.
2 CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of mass air flow and intake
air temperature sensor signal using Subaru
Select Monitor.
NOTE:
For detailed operation procedure, refer to the
"READ CURRENT DATA FOR ENGINE". <Ref.
to EN(H4SO 2.5)(diag)-26, Subaru Select Mon-
itor.>
3 CHECK HARNESS BETWEEN MASS AIR
FLOW AND INTAKE AIR TEMPERATURE
SENSOR AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from mass air
flow and intake air temperature sensor.
3) Turn the ignition switch to ON.
4) Read the data of mass air flow and intake
air temperature sensor signal using Subaru
Select Monitor.
NOTE:
For detailed operation procedure, refer to the
"READ CURRENT DATA FOR ENGINE". <Ref.
to EN(H4SO 2.5)(diag)-26, Subaru Select Mon-
itor.>
Check
Is the option code EC, EK or
K4?
Is the intake air temperature
more than 120#C (248#F)?
Is the intake air temperature
less than "40#C ("40#F)?
EN(H4SO 2.5)(diag)-104
Yes
Go to step 2. Refer to EN(H4SO
2.0) section. <Ref.
to EN(H4SO
2.0)(diag)-66, List
of Diagnostic Trou-
ble Code (DTC).>
NOTE:
Fuel injection sys-
tem for KA and KS
model is the same
as 2.0 L model.
Go to step 3. Repair the poor
contact.
NOTE:
In this case, repair
the following:
• Poor contact in
mass air flow and
intake air tempera-
ture sensor
• Poor contact in
ECM
• Poor contact in
coupling connector
• Poor contact in
joint connector
Replace the mass Repair the ground
air flow and intake short circuit in har-
air temperature ness between
sensor. <Ref. to mass air flow and
FU(H4SO 2.5)-26, intake air tempera-
Mass Air Flow and ture sensor and
Intake Air Temper- ECM connector.
ature Sensor.>
No