Subaru Legacy 2004 Service Manual page 955

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of throttle position sensor
signal using Subaru Select Monitor or 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 2.5)(diag)-26, Subaru Select
Monitor.>
• OBD-II general scan tool
For detailed operation procedures, refer to the
operation manual of OBD-II general scan tool.
2 CHECK HARNESS BETWEEN TUMBLE
GENERATOR VALVE POSITION SENSOR
AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from throttle
position sensor.
3) Measure the resistance of harness
between throttle position sensor connector and
engine ground.
Connector & terminal
(E50) No. 2 — Engine ground:
3 CHECK HARNESS BETWEEN THROTTLE
POSITION SENSOR AND ECM CONNEC-
TOR.
1) Turn the ignition switch to ON.
2) Measure the voltage between throttle posi-
tion sensor connector and engine ground.
Connector & terminal
(E50) No. 3 (+) — Engine ground (
Check
Is the voltage more than 4.9 V? Go to step 2.
Is the resistance less than 5
!?
Is the voltage more than 4.9 V? Repair the battery
"
):
EN(H4SO 2.5)(diag)-196
Yes
Even if malfunction
indicator light
lights up, the cir-
cuit has returned
to a normal condi-
tion at this time. A
temporary poor
contact of the con-
nector may be the
cause.
NOTE:
In this case, repair
the following:
• Poor contact in
tumble generator
valve position sen-
sor connector
• Poor contact in
ECM connector
• Poor contact in
coupling connector
Go to step 3. Repair the har-
ness and connec-
tor.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
tumble generator
valve position sen-
sor and ECM con-
nector
• Poor contact in
coupling connector
• Poor contact in
joint connector
Replace the tum-
short circuit in har- ble generator valve
ness between tum- assembly. <Ref. to
ble generator valve FU(H4SO 2.5)-28,
position sensor Tumble Generator
and ECM connec- Valve Assembly.>
tor. After repair,
replace the ECM.
<Ref. to FU(H4SO
2.5)-36, Engine
Control Module
(ECM).>
No