Subaru IMPREZA 2002 Service Manual page 508

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
ENGINE (DIAGNOSTICS)
AP:DTC PO420
-
CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD
-
DTC DETECTING CONDITION:
TROUBLE SYMPTOM:
Two consecutive driving cycles with fault
Engine stalls.
Idle mixture
is
out of specifications.
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(S0HC)-43, OP-
ERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(SOHC)BO, OPERATION, Inspec-
tion Mode.>.
WIRING DIAGRAM:
A @ C @ ECM
EN 1092
EN(S0HC)-184