Subaru Legacy III (2000-2003 year). Manual — part 211

EN(H4SOw/oOBD)-34

ENGINE (DIAGNOSTICS)

ENGINE MALFUNCTION INDICATOR LAMP (MIL)

D: CHECK ENGINE MALFUNCTION INDICATOR LAMP (MIL) DOES NOT GO

OFF.

• DIAGNOSIS:

• The CHECK ENGINE malfunction indicator lamp (MIL) circuit is shorted.

• TROUBLE SYMPTOM:

• Although MIL comes on when engine runs, trouble code is not shown on Subaru select monitor or OBD-
II general scan tool display.

• WIRING DIAGRAM:

Step

Value

Yes

No

1

CHECK HARNESS BETWEEN COMBINA-
TION METER AND ECM CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from ECM.
3) Turn ignition switch to ON.

Does the MIL come on?

MIL illuminates.

Repair short circuit
in harness
between combina-
tion meter and
ECM connector.

Replace ECM.
<Ref. to
FU(H4SOw/
oOBD)-42, Engine
Control Module.>

EN-01043

IGNITION
RELAY

SBF-4

No. 5

SBF-1

A4

4

1

B157

B72

B134

B36

i1

IGNITION
SWITCH

B36

B4 B5 B6

A4 A5 A6

C5 C6

F6

D4 D5 D6

F1

H1

C4

G6

G1

C2

K1

M1 M2

K6

L1

D1 D2

A1 A2
B1 B2

I6

J6

L2

I1

J1

H6

M4 M5 M6

L4 L5 L6

N5 N6

O4 O5 O6

N4

P4 P5

N2

O1 O2

P1 P2

N3

O3

P3

P6

A3

B3

C3

E4 E5 E6

E1 E2

B134

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

i12

B152

1 2 3

4 5 6

7 8 9 10 11 12 13 14

B72

3 4

1 2

BATTERY

11

ECM

B157

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

1 2

9

3 4

5 6

7 8

COMBINATION
METER

5

3

i12

3

*

4

*

1

*

2

*

3

*

4

*

1

*

2

*

LHD : 10
RHD : 37

LHD : 11
RHD : 34

LHD : 13
RHD : 36

LHD : 9
RHD : 38

D3

B11

FUSE &
RELAY
BOX

i5

B :

B152

D :

i5

1 2 3

4 5

6 7 8 9 10 11 12

EN(H4SOw/oOBD)-35

ENGINE (DIAGNOSTICS)

ENGINE MALFUNCTION INDICATOR LAMP (MIL)

E: CHECK ENGINE MALFUNCTION INDICATOR LAMP (MIL) DOES NOT BLINK

AT A CYCLE OF 3 Hz.

• DIAGNOSIS:

• The CHECK ENGINE malfunction indicator lamp (MIL) circuit is open or shorted.
• Test mode connector circuit is in open.

• TROUBLE SYMPTOM:

• When inspection mode, MIL does not blink at a cycle of 3 Hz.

• WIRING DIAGRAM:

EN-01044

IGNITION
RELAY

SBF-4

No. 5

SBF-1

4

1

B157

B72

IGNITION
SWITCH

BATTERY

COMBINATION
METER

5

3

i12

B36

B4 B5 B6

A4 A5 A6

C5 C6

F6

D4 D5 D6

F1

H1

C4

G6

G1

C2

K1

M1 M2

K6

L1

D1 D2

A1 A2
B1 B2

I6

J6

L2

I1

J1

H6

M4 M5 M6

L4 L5 L6

N5 N6

O4 O5 O6

N4

P4 P5

N2

O1 O2

P1 P2

N3

O3

P3

P6

A3

B3

C3

E4 E5 E6

E1 E2

B134

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

B157

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

1 2

9

3 4

5 6

7 8

i12

1 2 3

4 5 6

7 8 9 10 11 12 13 14

B72

3 4

1 2

B75

B76

1
2

1
2

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

B135

1

1

B36

i1

B75

B76

A4

B22

E3

A11

B14

B: B135

A: B134

ECM

16

3

*

4

*

1

*

2

*

LHD : 10
RHD : 37

LHD : 11
RHD : 34

LHD : 13
RHD : 36

LHD : 9
RHD : 38

3

*

4

*

1

*

2

*

B22

1 2 3 4
5 6 7 8
9 10 11 12

13 14 15 16

B152

i5

1 2 3

4 5

6 7 8 9 10 11 12

D3

B11

FUSE &
RELAY
BOX

i5

B :

B152

D :

EN(H4SOw/oOBD)-36

ENGINE (DIAGNOSTICS)

ENGINE MALFUNCTION INDICATOR LAMP (MIL)

Step

Value

Yes

No

1

CHECK STATUS OF CHECK ENGINE MAL-
FUNCTION INDICATOR LAMP (MIL).
1) Turn ignition switch to OFF.
2) Disconnect test mode connector.
3) Turn ignition switch to ON.

Does the MIL come on?

MIL illuminates.

Go to step 2.

Repair the MIL cir-
cuit. <Ref. to
EN(H4SOw/
oOBD)-31,
CHECK ENGINE
MALFUNCTION
INDICATOR
LAMP (MIL)
DOES NOT
COME ON.,
Engine Malfunc-
tion Indicator
Lamp (MIL).>

2

CHECK OUTPUT SIGNAL FROM ECM.
Measure voltage between test mode connector
and chassis ground.

Connector & terminal

(B75) No. 1 (+) — Chassis ground (

−−−−

):

Is the measured value less than the specified
value?

1 V

Go to step 3.

Go to step 5.

3

CHECK HARNESS BETWEEN ECM AND
TEST MODE CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from ECM.
3) Measure resistance of harness between

ECM and test mode connector.

Connector & terminal

(B135) No. 14 — (B75) No. 1:

Is the measured value less than the speci-
fied value?

1

Ω

Go to step 4.

Repair harness
and connector.

NOTE:
In this case, repair
the following:
• Open circuit in
harness between
ECM and test
mode connector

4

CHECK POOR CONTACT.
Check poor contact in ECM connector.
Is there poor contact in ECM connector?

There is poor contact.

Repair poor con-
tact in ECM con-
nector.

Replace ECM.
<Ref. to
FU(H4SOw/
oOBD)-42, Engine
Control Module.>

5

CHECK HARNESS BETWEEN TEST MODE
CONNECTOR AND CHASSIS GROUND.
1) Turn ignition switch to OFF.
2) Disconnect connector from ECM.
3) Measure resistance of harness between

test mode connector and chassis ground.

Connector & terminal

(B76) No. 1 — Chassis ground:

Is the measured value less than the speci-
fied value?

1

Ω

Go to step 6.

Repair harness
and connector.

NOTE:
In this case, repair
the following:
• Open circuit in
harness between
test mode connec-
tor and chassis
ground

6

CHECK POOR CONTACT.
Check poor contact in ECM connector.
Is there poor contact in ECM connector?

There is poor contact.

Repair poor con-
tact in ECM con-
nector.

Replace ECM.
<Ref. to
FU(H4SOw/
oOBD)-42, Engine
Control Module.>

EN(H4SOw/oOBD)-37

ENGINE (DIAGNOSTICS)

ENGINE MALFUNCTION INDICATOR LAMP (MIL)

F: CHECK ENGINE MALFUNCTION INDICATOR LAMP (MIL) REMAINS BLINK-

ING AT A CYCLE OF 3 Hz.

• DIAGNOSIS:

• Test mode connector circuit is shorted.

• TROUBLE SYMPTOM:

• Even though test mode connector is disconnected, MIL blinks at a cycle of 3 Hz when ignition switch is
turned to ON.

• WIRING DIAGRAM:

EN-01044

IGNITION
RELAY

SBF-4

No. 5

SBF-1

4

1

B157

B72

IGNITION
SWITCH

BATTERY

COMBINATION
METER

5

3

i12

B36

B4 B5 B6

A4 A5 A6

C5 C6

F6

D4 D5 D6

F1

H1

C4

G6

G1

C2

K1

M1 M2

K6

L1

D1 D2

A1 A2
B1 B2

I6

J6

L2

I1

J1

H6

M4 M5 M6

L4 L5 L6

N5 N6

O4 O5 O6

N4

P4 P5

N2

O1 O2

P1 P2

N3

O3

P3

P6

A3

B3

C3

E4 E5 E6

E1 E2

B134

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

B157

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

1 2

9

3 4

5 6

7 8

i12

1 2 3

4 5 6

7 8 9 10 11 12 13 14

B72

3 4

1 2

B75

B76

1
2

1
2

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

B135

1

1

B36

i1

B75

B76

A4

B22

E3

A11

B14

B: B135

A: B134

ECM

16

3

*

4

*

1

*

2

*

LHD : 10
RHD : 37

LHD : 11
RHD : 34

LHD : 13
RHD : 36

LHD : 9
RHD : 38

3

*

4

*

1

*

2

*

B22

1 2 3 4
5 6 7 8
9 10 11 12

13 14 15 16

B152

i5

1 2 3

4 5

6 7 8 9 10 11 12

D3

B11

FUSE &
RELAY
BOX

i5

B :

B152

D :