Subaru 2009 IMPREZA Service Manual page 597

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
AW:DTC P0304 CYLINDER 4 MISFIRE DETECTED
DTC DETECTING CONDITION:
• Detected when two consecutive driving cycles with fault occur.
• Immediately at fault recognition (A misfire which could damage catalyst occurs.)
• GENERAL DESCRIPTION<Ref. to GD(H4SO)-83, DTC P0304 CYLINDER 4 MISFIRE DETECTED, Di-
agnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
• Engine stalls.
• Improper idling
• Rough driving
CAUTION:
After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(H4SO)(diag)-55,
OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4SO)(diag)-44, PROCEDURE,
Inspection Mode.>.
WIRING DIAGRAM:
MAIN RELAY
37
38
39
40
B220
FUEL INJECTOR
No. 1
E5 E16
E6 E17
1 2
B220
4
E5 E16
FUEL INJECTOR
No. 2
B220
1 2 9 13 17 21
10 14 18 22
3 4
11 12 15 16 19 20 23 24
5 6
7 8 25 29 33 37
26 30 34 38
27 28 31 32 35 36 39 40
EN(H4SO)(diag)-180
FUSE
(RELAY BLOCK)
SBF-7
3
B137 ECM
E6
FUEL INJECTOR
No. 3
B21
1 2 3 4 5 6 7 8 9 10 11
12 13 14 15 16 17 18 19 20 21 22
23 24 25 26 27 28 29 30 31 32 33
34 35 36 37 38 39 40 41
42 43 44 45 46 47
48 49 50 51 52 53 54
BATTERY
B21
E2
E17
FUEL INJECTOR
No. 4
B137
1 2 3 4 5 6
8 9 10 11 12 13 14 15 16 17
18 19 20 21 22 23 24 25
26 27 28 29 30 31
E
7
EN-06633