Subaru Legacy 2004 Service Manual page 865

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 air flow and intake air tem-
perature 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) Measure the voltage between mass air flow
and intake air temperature sensor connector
and engine ground.
Connector & terminal
(B3) No. 4 (+) — Engine ground (
4 CHECK HARNESS BETWEEN MASS AIR
FLOW AND INTAKE AIR TEMPERATURE
SENSOR AND ECM CONNECTOR.
1) Turn the ignition switch to ON.
2) Measure the voltage between mass air flow
and intake air temperature sensor connector
and engine ground.
Connector & terminal
(B3) No. 4 (+) — Engine ground (
Check
Is the option code EC, EK or
K4?
Is the intake air temperature
less than "40#C ("40#F)?
Is the voltage more than 10 V? Repair the battery
"
):
Is the voltage more than 10 V? Repair the battery
"
):
EN(H4SO 2.5)(diag)-106
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
Go to step 4.
short circuit in har-
ness between
mass air flow and
intake air tempera-
ture sensor and
ECM connector.
Go to step 5.
short circuit in har-
ness between
mass air flow and
intake air tempera-
ture sensor and
ECM connector.
No