Subaru Legacy III (2000-2003 year). Manual — part 110

EN(H4SO)-52

ENGINE (DIAGNOSTICS)

ENGINE MALFUNCTION INDICATOR LAMP (MI)

C: CHECK ENGINE MALFUNCTION INDICATOR LAMP (MI) DOES NOT COME

ON.

• DIAGNOSIS:

• The CHECK ENGINE malfunction indicator lamp (MI) circuit is open or shorted.

• TROUBLE SYMPTOM:

• When ignition switch is turned ON (engine OFF), MI does not come on.

• WIRING DIAGRAM:

EN-01116

LHD MODEL : 10
RHD MODEL : 37

1

*

2

*

3

*

4

*

5

*

LHD MODEL : 11
RHD MODEL : 34

LHD MODEL : 13
RHD MODEL : 36

LHD MODEL : 9
RHD MODEL : 38

LHD MODEL : 12
RHD MODEL : 15

5

*

IGNITION
RELAY

SBF-4

No. 5

SBF-1

4

1

B157

B72

B134

B36

i1

IGNITION
SWITCH

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

B72

3 4

1 2

BATTERY

28

ECM

COMBINATION
METER

3

i12

A4

i12

1 2 3

4 5 6

7 8 9 10 11 12 13 14

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

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

1

*

2

*

3

*

4

*

EN(H4SO)-53

ENGINE (DIAGNOSTICS)

ENGINE MALFUNCTION INDICATOR LAMP (MI)

Step

Value

Yes

No

1

CHECK OUTPUT SIGNAL FROM ECM.
1) Turn ignition switch to ON.
2) Measure voltage between ECM connector

and chassis ground.

Connector & terminal

(B134) No. 28 (+) — Chassis ground (

−−−−

):

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

1 V

Go to step 4.

Go to step 2.

2

CHECK POOR CONTACT.
Does the MI come on when shaking or pulling
ECM connector and harness?

MI illuminates.

Repair poor con-
tact in ECM con-
nector.

Go to step 3.

3

CHECK ECM CONNECTOR.
Is ECM connector correctly connected?

Connected.

Replace ECM.
<Ref. to
FU(H4SO)-45,
Engine Control
Module.>

Repair connection
of ECM connector.

4

CHECK HARNESS BETWEEN COMBINA-
TION METER AND ECM CONNECTOR.
1) Turn ignition switch to OFF.
2) Remove combination meter. <Ref. to IDI-

14, Combination Meter Assembly.>

3) Disconnect connector from ECM and com-

bination meter.

4) Measure resistance of harness between

ECM and combination meter connector.

Connector & terminal

(B134) No. 28 — (i12) No. 12: (LHD
model)
(B134) No. 28 — (i12) No. 15: (RHD
model)

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

1 Ω

Go to step 5.

Repair harness
and connector.

NOTE:
In this case, repair
the following:
• Open circuit in
harness between
ECM and combi-
nation meter con-
nector
• Poor contact in
coupling connector

5

CHECK POOR CONTACT.
Check poor contact in combination meter con-
nector.
Is there poor contact in combination meter
connector?

There is poor contact.

Repair poor con-
tact in combination
meter connector.

Go to step 6.

EN(H4SO)-54

ENGINE (DIAGNOSTICS)

ENGINE MALFUNCTION INDICATOR LAMP (MI)

6

CHECK HARNESS BETWEEN COMBINA-
TION METER AND IGNITION SWITCH CON-
NECTOR.
1) Turn ignition switch to ON.
2) Measure voltage between combination

meter connector and chassis ground.

Connector & terminal

(i12) No. 3 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

10 V

Go to step 7.

Check the follow-
ing and repair if
necessary.

NOTE:
• Broken down
ignition relay.
• Blown out fuse
(No. 5).
• If replaced fuse
(No. 5) blows eas-
ily, check the har-
ness for short
circuit of harness
between fuse (No.
5) and ignition
relay connector.
• Open or short
circuit in harness
between fuse (No.
5) and battery ter-
minal
• Open circuit in
harness between
fuse (No. 5) and
ignition relay con-
nector
• Poor contact in
ignition relay con-
nector
• Poor contact in
ignition switch
connector

7

CHECK LAMP BULB.
Remove engine malfunction indicator lamp
bulb.
Is lamp bulb condition OK?

OK

Repair combina-
tion meter connec-
tor.

Replace lamp
bulb.

Step

Value

Yes

No

EN(H4SO)-55

ENGINE (DIAGNOSTICS)

ENGINE MALFUNCTION INDICATOR LAMP (MI)

MEMO: