Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual - part 236
EN(H4DOTC)(diag)-168
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
• Models with SI-DRIVE <Ref. to WI-48, WITH SI-DRIVE, WIRING DIAGRAM, Engine Electrical System.>
Step
Check
Yes
No
1
CHECK REAR OXYGEN SENSOR DATA.
1) Warm up the engine until engine coolant
temperature is higher than 75°C (167°F), and
keep the engine speed at 3,000 rpm. (2 minutes
maximum)
2) Read the value of «Rear O2 Sensor» using
the Subaru Select Monitor or a general scan
tool.
NOTE:
• Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H4DOTC)(diag)-40, Subaru Select Moni-
tor.>
• General scan tool
For detailed operation procedures, refer to the
general scan tool operation manual.
Is the value of «Rear O2 Sen-
sor» 0.490 V or more?
ECM
6
4 5
3
2
1
*
2
1
B220
15A
9
10
11
12
B220
*
*
1 2
3 4
D1
36
D3 A4
40
34
35
B21
E2
A6
A3
B220
13
14
15 16
17
27
24
25
26
20
21
22
23
29
30
31
28
32 35
33
34
37
38
39
36
40
8
9
10
11 12
1
2
5
3
4
7
6
19
18
B134
5
6
7
8
2
1
9
4
3
10
24
22 23
25
11 12 13 14 15
26 27
28
16 17
18 19 20 21
33 34
29
32
30 31
A:
D: B137
C: B136
B: B135
A:
T6
B134
C9
B30
C20
B6
*
*
B21
1 2 3 4
12 13 14 15
5 6 7 8
16 17 18 19
9 10 11
20 21 22
23 24 25 26 27 28 29 30 31 32 33
35
34
37
36
39
38
41
40
43
42
44 45
47
46
49
48
51
50
53
52
54
4
1
3
4
1
3
B19
T5
22
T5
B19
5
6
7
8
2
1
9
4
3
10
22 23
11 12 13 14 15
24 25
26
16 17
18 19 20 21
27
28 29
30 31
B135
B:
5
6
7
8
2
1
9
4
3
10
24
22 23
25
11 12 13 14 15
26 27
28
16 17 18 19
20 21
29 30 31
32 33
34 35
B136
C:
5
6
7 8
2
1
9
4
3
10
24
22 23
25
11 12 13 14 15
26 27
28
16
17 18 19 20 21
33 34
29
32
30
31
35
D: B137
B19
T6
B83
B138
B138
B83
EN-08723
SBF-5
E
E
BATTERY
: TERMINAL No. OPTIONAL ARRANGEMENT
REAR
OXYGEN SENSOR
A/F, OXYGEN SENSOR
RELAY
FUSE
(RELAY BLOCK)