Subaru Legacy 2003 Service Manual page 624

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK ANY OTHER DTC ON DISPLAY.
Is any other DTC displayed?
2 CHECK AIR BY-PASS LINE.
1) Turn ignition switch to OFF.
2) Remove idle air control solenoid valve from
throttle body. <Ref. to FU(H4SO)-34,
REMOVAL, Idle Air Control Solenoid
Valve.>
3) Remove throttle body from intake manifold.
<Ref. to FU(H4SO)-14, REMOVAL, Throt-
tle Body.>
4) Using an air gun, force air into idle air con-
trol solenoid valve installation area. Confirm
that forced air subsequently escapes from
throttle body interior.
Does air flow out?
Value
DTC indicated.
Flows out.
EN(H4SO)-227
ENGINE (DIAGNOSTICS)
Yes
Inspect the rele- Go to step 2.
vant DTC using
"List of Diagnostic
Trouble Code
(DTC)". <Ref. to
EN(H4SO)-83, List
of Diagnostic
Trouble Code
(DTC).>
NOTE:
In this case, it is
not necessary to
inspect DTC
P0506.
Replace idle air Replace throttle
control solenoid body. <Ref. to
valve. <Ref. to FU(H4SO)-14,
FU(H4SO)-34, INSTALLATION,
INSTALLATION, Throttle Body.>
Idle Air Control
Solenoid Valve.>
No