Subaru Legacy 2002 Service Manual page 730

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
No.
1 CHECK ANY OTHER DTC ON DISPLAY.
2 CHECK AIR INTAKE SYSTEM.
1) Turn ignition switch to ON.
2) Start engine, and idle it.
3) Check the following items.
¼ Loose installation of intake manifold, idle air
control solenoid valve and throttle body
¼ Cracks of intake manifold gasket, idle air
control solenoid valve gasket and throttle
body gasket
¼ Disconnections of vacuum hoses
3 CHECK THROTTLE CABLE.
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-39, REMOVAL, Idle
Air Control Solenoid Valve.>
3) Confirm that there are no foreign particles
in by-pass air line.
Step
Does the Subaru Select
Monitor or OBD-II general
scan tool indicate DTC
P1510, P1511, P1512,
P1513, P1514, P1515,
P1516 or P1517?
Is there a fault in air intake
system?
Does throttle cable have
play for adjustment?
Are foreign particles in by-
pass air line?
EN-213
Check Yes
Inspect DTC
P1510, P1511,
P1512, P1513,
P1514, P1515,
P1516 or P1517
using "17. List of
Diagnostic
Trouble Code
(DTC)". <Ref. to
EN-82, List of
Diagnostic
Trouble Code
(DTC).>
NOTE:
In this case, it is
not necessary to
inspect DTC
P0507.
Repair air suction
and leaks.
Go to step 4.
Remove foreign
particles from by-
pass air line.
Engine (Diagnostics)
No
Go to step 2.
Go to step 3.
Adjust throttle
cable. <Ref. to
SP-9, Accelerator
Control Cable.>
Replace idle air
control solenoid
valve. <Ref. to
FU-39, Idle Air
Control Solenoid
Valve.>