Subaru Legacy 2004 Service Manual page 524

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of intake air temperature
sensor signal using Subaru Select Monitor.
NOTE:
For detailed operation procedure, refer to
"READ CURRENT DATA FOR ENGINE". <Ref.
to EN(H4SO 2.0)(diag)-25, Subaru Select Mon-
itor.>
2 CHECK HARNESS BETWEEN INTAKE AIR
TEMPERATURE SENSOR AND ECM CON-
NECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from intake air
temperature sensor.
3) Measure the voltage between intake air
temperature sensor connector and engine
ground.
Connector & terminal
(B136) No. 28 (+) — Engine ground (
3 CHECK HARNESS BETWEEN INTAKE AIR
TEMPERATURE SENSOR AND ECM CON-
NECTOR.
1) Turn the ignition switch to ON.
2) Measure the voltage between intake air
temperature sensor connector and engine
ground.
Connector & terminal
(B136) No. 28 (+) — Engine ground (
4 CHECK HARNESS BETWEEN INTAKE AIR
TEMPERATURE SENSOR AND ECM CON-
NECTOR.
Measure the voltage between intake air tem-
perature sensor connector and engine ground.
Connector & terminal
(B136) No. 28 (+) — Engine ground (
Check
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
"
):
Is the voltage more than 3 V?
"
):
EN(H4SO 2.0)(diag)-92
Yes
Go to step 2. Repair the poor
contact.
NOTE:
In this case, repair
the following:
• Poor contact in
intake air tempera-
ture sensor
• Poor contact in
ECM
• Poor contact in
coupling connector
• Poor contact in
joint connector
Go to step 3.
short circuit in har-
ness between
intake air tempera-
ture sensor and
ECM connector.
Go to step 4.
short circuit in har-
ness between
intake air tempera-
ture sensor and
ECM connector.
Go to step 5. Repair the har-
ness and connec-
tor.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
intake air tempera-
ture sensor and
ECM connector
• Poor contact in
intake air tempera-
ture sensor
• Poor contact in
ECM
• Poor contact in
coupling connector
• Poor contact in
joint connector
No