Subaru 2002 IMPREZA Service Manual page 473

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
ENGINE fDIAGNOSTICS)
Check
Ioes the Subaru Select Moni-
or or OBD-ll general scan tool
ndicate DTC PO508 or P509?
Ioes air flow out?
Step
CHECK ANY OTHER DTC ON DISPLAY.
Yes
Inspect DTC
PO505 or P I 505
using "List of Diag-
nostic Trouble
Code (DTC)".
<Ref. to EN(D0HC
TURBO)-80, List
of Diagnostic Trou-
ble Code (DTC).>
NOTE:
In this case, it is
not necessary to
inspect DTC
P0506.
Go to step 4.
CHECK IDLE AIR CONTROL SOLENOID
VALVE.
1)Turn the ignition switch to OFF.
2)Remove the idle air control solenoid valve
from throttle body. <Ref. to FU(D0HC
TURBO)-36, REMOVAL, Idle Air Control Sole.
noid Valve.>
3)Using an air gun, force air into the idle air
control solenoid valve by-pass air inlet. Con-
firm that forced air subsequently escapes from
both main air passage and assist air passage.
CHECK IDLE AIR CONTROL SOLENOID
VALVE DUTY RATIO.
1)Turn the ignition switch to ON.
2)Start the engine, and warm-up the engine.
3)Turn all accessory switches to OFF.
4)Read the data of idle air control solenoid
valve duty ratio using Subaru Select Monitor
01
OBD-II general scan tool.
NOTE:
Gubaru Select Monitor
For detailed operation procedures, refer
to
the
"READ CURRENT DATA FOR ENGINE". <Ref.
to EN(D0HC TURBO)-38, Subaru Select Mon
itor.>
*OBD-ll general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Instruction Manual.
1)Turn the ignition switch to OFF.
2)Remove the idle air control solenoid valve
from throttle body. <Ref. to FU(D0HC
TURBO)-36, REMOVAL, Idle Air Control Sole,
noid Valve.>
3)Remove the throttle body to intake manifold.
<Ref. to FU(D0HC TURBO)-14, REMOVAL,
Throttle Body.>
4)Using an air gun, force air into the solenoid
valve installation area and throttle valve inte-
rior. Confirm that forced air subsequently
escapes from both these areas.
1 CHECK BY-PASS AIR LINE.
s the value more than 60%? Go to step 4.
I
loes air flow out?
Replace the idle
air control solenoid
valve. <Ref. to
FU(D0HC
TURBO)-36, Idle
Air Control Sole-
noid Valve.>
No
20 to step 2.
3eplace the idle
iir control solenoid
ialve. <Ref. to
-U(DOHC
rURBO)-36, Idle
4ir Control Sole-
ioid Valve.> After
.eplace, Go to step
5.
END.
3eplace the throt-
le body. <Ref. to
'U(D0HC
Throttle Body.>
rURBO)-14,
EN(D0HC TURBO)-249