Subaru Forester 2004 Service Manual page 164

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of exhaust temperature sen-
sor signal using Subaru Select Monitor or
OBD-II general scan tool.
NOTE:
• Subaru Select Monitor
For detailed operation procedure, refer to
"READ CURRENT DATA SHOWN ON DIS-
PLAY FOR ENGINE". <Ref. to EN(H4DOTC
2.5)-27, Subaru Select Monitor.>
• OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Operation Manual.
2 CHECK HARNESS BETWEEN EXHAUST
TEMPERATURE SENSOR AND ECM CON-
NECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from exhaust
temperature sensor.
3) Measure the voltage between exhaust tem-
perature sensor connector and engine ground.
Connector & terminal
(B279) No. 1 (+) — Engine ground (
3 CHECK HARNESS BETWEEN EXHAUST
TEMPERATURE SENSOR AND ECM CON-
NECTOR.
1) Turn the ignition switch to ON.
2) Measure the voltage between exhaust tem-
perature sensor connector and engine ground.
Connector & terminal
(B279) No. 1 (+) — Engine ground (
4 CHECK HARNESS BETWEEN EXHAUST
TEMPERATURE SENSOR AND ECM CON-
NECTOR.
Measure the voltage between exhaust temper-
ature sensor connector and engine ground.
Connector & terminal
(B279) No. 1 (+) — Engine ground (
Check
Is the temperature less than
372°C (702°F)?
Is the voltage more than 10 V? Repair battery
−
):
Is the voltage more than 10 V? Repair battery
−
):
Is the voltage more than 4 V?
−
):
EN(H4DOTC 2.5)-163
ENGINE (DIAGNOSTIC)
Yes
Go to step 2. Repair the poor
contact.
NOTE:
In this case repair
the following:
• Poor contact of
exhaust tempera-
ture sensor
• Poor contact in
ECM
• Poor contact in
joint connector
Go to step 3.
short circuit in har-
ness between
ECM and exhaust
temperature sen-
sor connector.
Go to step 4.
short circuit in har-
ness between
ECM and exhaust
temperature sen-
sor connector.
Go to step 5. Repair the harness
and connector.
NOTE:
In this case repair
the following:
• Open circuit in
harness between
ECM and exhaust
temperature sen-
sor connector
• Poor contact of
exhaust tempera-
ture sensor con-
nector
• Poor contact in
ECM connector.
• Poor contact in
joint connector
No