Subaru Legacy 2003 Service Manual page 591

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
ENGINE (DIAGNOSTICS)
AN:DTC P0420 — CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD
(BANK 1) —
• DTC DETECTING CONDITION:
• Two consecutive driving cycles with fault
• TROUBLE SYMPTOM:
• Engine stalls.
• Idle mixture is out of specifications.
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode<Ref. to EN(H4SO)-47, OPER-
ATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4SO)-40, OPERATION, Inspection
Mode.> .
• WIRING DIAGRAM:
MAIN RELAY
6
4
5
3
2
1
B47
EG FG
2 3
4 1
B83
: FOR G.C.C COUNTRIES
FG
MODEL
: EXCEPT FOR G.C.C
EG
COUNTRIES MODEL
B19 B18
T6
2 1
4 3
2 1
4 3
B137
1 2
5
6 7 8 9 10 11
14 15 16 17 18
B19
T5
REAR
OXYGEN
SENSOR
T6
T5
B19
B: C: D:
B135 B136
B47 B83
1 2
1 2 3 4 5 6
3 4
5 6
B136
4
1 2 3
3 4
7 8 9 10 11 12 13 14 15 16 17
12 13
18 19 20 21 22 23 24
19 20
EN(H4SO)-194
6 LHD
LHD
F44
B61
FRONT OXYGEN
( A/F ) SENSOR
B18
ECM
B137
F44
1 2 3 4
5 6 7 8
B135
5 6
1 2 3 4
8 9
10 11 12 13 14 15 16 17 18 19
25 26
20 21 22 23 24 25 26
BATTERY
SBF-5
5 6 7
27 28
EN-01130