Subaru Legacy 2002 Service Manual page 1460

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
No.
1 CHECK ANY OTHER DTC ON DISPLAY.
2 CHECK IDLE AIR CONTROL SOLENOID
VALVE.
1) Turn ignition switch to OFF.
2) Remove idle air control solenoid valve from
throttle body. <Ref. to FU(H6)-36, REMOVAL,
Idle Air Control Solenoid Valve.>
3) Using an air gun, force air into idle air con-
trol solenoid valve by-pass air inlet. Confirm
that forced air subsequently escapes from
both main air passage and assist air passage.
3 CHECK IDLE AIR CONTROL SOLENOID
VALVE DUTY RATIO.
1) Turn ignition switch to ON.
2) Start engine, and warm-up the engine.
3) Turn all accessory switches to OFF.
4) Read data of idle air control solenoid valve
duty ratio using Subaru Select Monitor or
OBD-II general scan tool.
NOTE:
¼ Subaru Select Monitor
For detailed operation procedures, refer to the
"READ CURRENT DATA FOR ENGINE".
<Ref. to EN(H6)-38, Subaru Select Monitor.>
¼ OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Instruction Manual.
4 CHECK BY-PASS AIR LINE.
1) Turn ignition switch to OFF.
2) Remove idle air control solenoid valve from
throttle body. <Ref. to FU(H6)-36, REMOVAL,
Idle Air Control Solenoid Valve.>
3) Remove throttle body to intake manifold.
<Ref. to FU(H6)-16, REMOVAL, Throttle
Body.>
4) Using an air gun, force air into solenoid
valve installation area and throttle valve inte-
rior. Confirm that forced air subsequently
escapes from both these areas.
Step
Is there any other DTC on
display?
Does air flow out?
Is the value more than
60%?
Does air flow out?
EN(H6)-253
Check Yes
Inspect the rel-
evant DTC using
"List of Diagnostic
Trouble Code
(DTC)". <Ref. to
EN(H6)-87, List of
Diagnostic
Trouble Code
(DTC).>
NOTE:
In this case, it is
not necessary to
inspect DTC
P0506.
Go to step 4.
Go to step 4.
Replace idle air
control solenoid
valve. <Ref. to
FU(H6)-36, Idle
Air Control Sole-
noid Valve.>
Engine (DIAGNOSTICS)
No
Go to step 2.
Replace idle air
control solenoid
valve. <Ref. to
FU(H6)-36, Idle
Air Control Sole-
noid Valve.> After
replace, Go to
step 3.
END.
Replace throttle
body. <Ref. to
FU(H6)-16,
Throttle Body.>