Subaru IMPREZA 2004 Service Manual page 498

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 CHECK ANY OTHER DTC ON DISPLAY.
2 CHECK AIR BY-PASS LINE.
1)Turn the ignition switch to OFF.
2)Remove the idle air control solenoid valve
from throttle body. <Ref. to FU(H4SO)-35,
REMOVAL, Idle Air Control Solenoid Valve.>
3)Remove the throttle body from intake mani-
fold. <Ref. to FU(H4SO)-15, REMOVAL, Throt-
tle Body.>
4)Using an air gun, force air into the idle air
control solenoid valve installation area. Con-
firm that forced air subsequently escapes from
throttle body interior.
Check
Is any other DTC displayed?
Does air flow out?
EN(H4SO)(diag)-189
ENGINE (DIAGNOSTICS)
Yes
Inspect DTC using Go to step 2.
"List of Diagnostic
Trouble Code
(DTC)". <Ref. to
EN(H4SO)(diag)-
74, List of Diag-
nostic Trouble
Code (DTC).>
NOTE:
In this case, it is
not necessary to
inspect
DTC P0506.
Replace the idle Replace the throt-
air control solenoid tle body. <Ref. to
valve. <Ref. to FU(H4SO)-15,
FU(H4SO)-35, INSTALLATION,
INSTALLATION, Throttle Body.>
Idle Air Control
Solenoid Valve.>
No