Mitsubishi Lancer Evolution IX. Manual - part 196

SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) USING SWS MONITOR

54C-43

COMMENTS ON TROUBLE SYMPTOM

It is suspected that the power supply circuit to the 
front-ECU is defective, or the wiring harness 
between the SWS monitor and the front-ECU or their 
connector(s) is damaged. If the battery power supply 
circuit to the ECU (terminal No.5 of the front-ECU) is 
damaged, also check the power supply circuit from 
the ignition switch (IG2) (terminal No.22 of the 
front-ECU), and repair if necessary.

POSSIBLE CAUSES

• Malfunction of the front-ECU

• Malfunction of the ETACS-ECU

• Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

Step 1. ECU check by using the SWS monitor.
Check that the power supply and earth lines to the 
ETACS-ECU and the SWS communication lines are 
normal.

• Ignition switch: OFF

ECUS TO BE CHECKED

• ETACS ECU

OK: "OK" is displayed on the "ETACS ECU" 
menu.

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Refer to Inspection Procedure A-3 
"Communication with the ETACS-ECU is 
not possible 

P.54C-36

."

Step 2. Connector check: A-10X front-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Repair the defective connector.

Step 3. Voltage measurement at A-10X front-ECU 
connector

(1) Disconnect the connector, and measure at the 

relay box side.

(2) Ignition switch: ON

(3) Voltage between A-10X front-ECU connector 

terminal No.7 and body earth

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Go to Step 4.

Step 4. Check the wiring harness between A-10X 
front-ECU connector terminal No.7 and the 
battery.

• Check the power supply line for open circuit.

AC310572AB

Connector: A-10X

Relay box side

10

11

5

9 8 7 6

4 3

1

2

Battery

AC310572AB

Connector: A-10X

Relay box side

10

11

5

9 8 7 6

4 3

1

2

Battery

AC301541CT

5

11

9

10

8 7 6

2

4 3

1

Connector A-10X
(Relay box side)

AC310572AB

Connector: A-10X

Relay box side

10

11

5

9 8 7 6

4 3

1

2

Battery

SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) USING SWS MONITOR

54C-44

Q: Is the check result normal?

YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00 

− How to 

Cope with Intermittent Malfunction 

P.00-5

).

NO : 

Repair the wiring harness.

Step 5. Connector check: A-11X front-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Repair the defective connector.

Step 6. Resistance measurement at A-11X 
front-ECU connector

(1) Disconnect the connector, and measure at the 

relay box side.

(2) Resistance between A-11X front-ECU connector 

terminal No.31 and body earth

OK: 2 

Ω or less

Q: Is the check result normal?

YES : 

Go to Step 8.

NO : 

Go to Step 7.

Step 7. Check the wiring harness between A-11X 
front-ECU terminal connector terminal No.31 and 
body earth.

• Check the earth wires for open circuit.

Q: Is the check result normal?

YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00 

− How to 

Cope with Intermittent Malfunction 

P.00-5

).

NO : 

Repair the wiring harness.

Step 8. Connector check: C-228 ETACS-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 9.

NO : 

Repair the defective connector.

AC310572AC

Connector: A-11X

Relay box side

Battery

29

31 30

28 27

25

26

24

21

22

23

AC310572AC

Connector: A-11X

Relay box side

Battery

29

31 30

28 27

25

26

24

21

22

23

AC301541CU

Connector A-11X
(Relay box side)

24

29

30

31

2827

25

26

21

2322

AC310572AC

Connector: A-11X

Relay box side

Battery

29

31 30

28 27

25

26

24

21

22

23

AC310450

Connector: C-228 <LHD>

AC

Junction block (rear view)

C-228 (GR)

Harness side

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

AC310461

Junction block (rear view)

Connector: C-228 <RHD>

AC

Harness side

C-228 (GR)

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) USING SWS MONITOR

54C-45

Step 9. Check the wiring harness between A-11X 
front-ECU connector terminal No.22 and C-228 
ETACS-ECU connector terminal No.59.

NOTE: 

Prior to the wiring harness inspection, check joint 
connector C-101 and intermediate connector C-129, 
and repair if necessary.

• Check the communication lines for open circuit.

Q: Is the check result normal?

YES : 

Go to Step 10.

NO : 

Repair the wiring harness.

AC310572AC

Connector: A-11X

Relay box side

Battery

29

31 30

28 27

25

26

24

21

22

23

AC310450

Connector: C-228 <LHD>

AC

Junction block (rear view)

C-228 (GR)

Harness side

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

AC310461

Junction block (rear view)

Connector: C-228 <RHD>

AC

Harness side

C-228 (GR)

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

AC310447

AG

Connectors: C-101, C-129 <LHD>

C-101 (L)

C-129

C-129

C-101

AC310456

Connector: C-101 <RHD>

AQ

C-101 (L)

AC310454

Connector: C-129 <RHD>

AV

SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) USING SWS MONITOR

54C-46

Step 10. ECU check by using the SWS monitor.
Check that the power supply and earth lines to the 
front-ECU and the SWS communication lines are 
normal.

• Ignition switch: ON

ECUS TO BE CHECKED

• FRONT ECU

OK: "OK" is displayed on the "FRONT ECU" 
menu.

Q: Is the check result normal?

YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00 

− How to 

Cope with Intermittent Malfunction 

P.00-5

).

NO : 

Replace the front-ECU.