Subaru Legacy 2002 Service Manual page 1391

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Engine (DIAGNOSTICS)
AB: DTC P0171 — FUEL TRIM #1 (RH) MALFUNCTION (A/F TOO LEAN) —
NOTE:
For the diagnostic procedure, refer to DTC P0172. <Ref. to EN(H6)-184, DTC P0172 — FUEL TRIM #1
(RH) MALFUNCTION (A/F TOO RICH) —, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
AC: DTC P0172 — FUEL TRIM #1 (RH) MALFUNCTION (A/F TOO RICH) —
¼ DTC DETECTING CONDITION:
¼ Two consecutive driving cycles with fault
¼ TROUBLE SYMPTOM:
¼ Erroneous idling
¼ Engine stalls.
¼ Poor driving performance
CAUTION:
After repair or replacement of faulty parts, conduct CLEAR MEMORY MODE <Ref. to EN(H6)-49,
OPERATION, Clear Memory Mode.> and INSPECTION MODE <Ref. to EN(H6)-46, OPERATION,
Inspection Mode.>.
No.
1 CHECK ANY OTHER DTC ON DISPLAY.
2 CHECK EXHAUST SYSTEM.
3 CHECK AIR INTAKE SYSTEM.
Step
Is there any other DTC on
display?
Are there holes or loose
bolts on exhaust system?
Are there holes, loose bolts
or disconnection of hose on
air intake system?
EN(H6)-184
Check Yes
Inspect the rel-
evant DTC using
"List of Diagnostic
Trouble Code
(DTC)". <Ref. to
EN(H6)-87, List of
Diagnostic
Trouble Code
(DTC).>
NOTE:
In this case, it is
not necessary to
inspect DTC
P0172.
Repair exhaust
system.
Repair air intake
system.
S048521H35
S048521H36
No
Go to step 2.
Go to step 3.
Go to step 4.