Subaru Legacy 2003 Service Manual page 626

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK ANY OTHER DTC ON DISPLAY.
Is any other DTC displayed?
2 CHECK AIR INTAKE SYSTEM.
1) Turn ignition switch to ON.
2) Start engine, and idle it.
3) Check the following items.
•Loose installation of intake manifold, idle air
control solenoid valve and throttle body
•Cracks of intake manifold gasket, idle air con-
trol solenoid valve gasket and throttle body
gasket
•Disconnections of vacuum hoses
Is there any fault in air intake system?
3 CHECK THROTTLE CABLE.
Does throttle cable have play for adjustment?
4 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) Confirm that there are no foreign particles
in by-pass air line.
Are foreign particles in by-pass air line?
Value
DTC indicated.
There is a fault.
Cable has play.
There are foreign particles.
EN(H4SO)-229
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
P0507.
Repair air suction Go to step 3.
and leaks.
Go to step 4. Adjust throttle
cable. <Ref. to
SP(H4SO)-10,
Accelerator Con-
trol Cable.>
Remove foreign Replace idle air
particles from by- control solenoid
pass air line. valve. <Ref. to
FU(H4SO)-34, Idle
Air Control Sole-
noid Valve.>
No