Subaru IMPREZA 2004 Service Manual page 414

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 CHECK CURRENT DATA.
1)Start the engine.
2)Read the data of intake air temperature sen-
sor signal using Subaru Select Monitor or the
OBD-II general scan tool.
NOTE:
•Subaru Select Monitor
For detailed operation procedure, refer to the
"READ CURRENT DATA FOR ENGINE".
<Ref. to EN(H4SO)(diag)-32, Subaru Select
Monitor.>
•OBD-II general scan tool
For detailed operation procedure, refer to the
OBD-II General Scan Tool Instruction Manual.
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)Turn the ignition switch to ON.
4)Read the data of intake air temperature sen-
sor signal using Subaru Select Monitor or the
OBD-II general scan tool.
NOTE:
•Subaru Select Monitor
For detailed operation procedure, refer to the
"READ CURRENT DATA FOR ENGINE".
<Ref. to EN(H4SO)(diag)-32, Subaru Select
Monitor.>
•OBD-II general scan tool
For detailed operation procedure, refer to the
OBD-II General Scan Tool Instruction Manual.
Check
Is the intake air temperature
more than 120°C (248°F)?
Is the intake air temperature
less than −40°C (−40°F)?
EN(H4SO)(diag)-105
ENGINE (DIAGNOSTICS)
Yes
Go to step 2. Repair poor con-
tact.
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
Replace the intake Repair ground
air temperature short circuit in har-
sensor. <Ref. to ness between
FU(H4SO)-34, intake air tempera-
Intake Air Temper- ture sensor and
ature Sensor.> ECM connector.
No