Mitsubishi Lancer Evolution IX. Manual - part 229

SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) USING SWS MONITOR

54C-175

DIAGNOSIS PROCEDURE

Step 1. ECU check by using the SWS monitor.
Check that the power supply and earth lines to the 
column switch (column-ECU) and the front-ECU and 
the SWS communication lines are normal.

• Ignition switch: OFF

ECUS TO BE CHECKED

• COLUMN ECU

• FRONT ECU

OK: "OK" is displayed for all the items

Q: Is the check result normal?

"OK" is displayed for all the items : 

Go to Step 2.

"NG" is displayed on the "COLUMN ECU" menu. : 

Refer to Inspection Procedure A-2 
"Communication with the column switch 
(column-ECU) is not possible 

P.54C-30

."

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

Refer to Inspection Procedure A-4 
"Communication with the front-ECU is not 
possible 

P.54C-42

."

Step 2. Function diagnosis by using the SWS 
monitor.
Check the SWS communication signal, which are 
related to the tail lamps.

<Selected item> LIGHTING - TAIL LAMP

• Ignition switch: ON

• Lighting switch: TAIL

OK: Normal conditions displayed for all the 
items

Q: Is the check result normal?

Normal conditions are displayed for all the items. : 

Go to Step 3.

Normal condition is not displayed for item 00, 01 or 
03. : 

Refer to Inspection Procedure L-4 "The 
column switch (lighting and turn-signal lamp 
switch) signal is not received 

P.54C-267

."

Normal condition is not displayed for item No.30. : 

Refer to Inspection Procedure L-2 "The 
ignition switch (IG1) signal is not received 

P.54C-261

."

Normal condition is not displayed for item No.35. : 

Refer to Inspection Procedure H-6 "The 
headlamp automatic shutdown function 
does not work normally 

P.54C-183

."

Normal condition is not displayed for item No.70. : 

Replace the front-ECU.

Item No. Item name

Normal condition

Item 00

HEADLAMP SW

ON when the 
lighting switch is at 
HEAD

Item 01

TAIL LAMP SW

ON when the 
lighting switch is at 
TAIL

Item 03

PASSING SW

OFF

Item 30

IG SW(IG1)

ON

Item 35

HD AUTO-CUT

OFF

Item 70

FRONT ECU ACK NORMAL ACK

SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) USING SWS MONITOR

54C-176

Step 3. Connector check: A-10X front-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Repair the defective connector.

Step 4. Voltage measurement at A-10X front-ECU 
connector

(1) Remove the front-ECU, and measure at the relay 

box side.

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

terminal No.5 and body earth

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Go to Step 5.

Step 5. Check the wiring harness between A-10X 
front-ECU connector terminal No.5 and the 
battery.

• Check the power supply line 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 6. Retest the system.
Check that the tail lamps illuminate normally.

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.

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

AC301541 DB

Connector A-10X
(Relay box side)

5

11

9

10

8 7 6

2

4 3

1

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-177

INSPECTION PROCEDURE H-3: The low-beam headlamps do not illuminate normally.

CAUTION

Whenever the ECU is replaced, ensure that the 
input and output signal circuits are normal.

COMMENTS ON TROUBLE SYMPTOM

If the low-beam headlamps do not illuminate, the 
headlamp switch input circuit or the front-ECU may 
be defective.

POSSIBLE CAUSES

• Malfunction of the column switch

• Malfunction of the front-ECU

• Damaged harness wires and connectors

Wire colour code
B : Black     LG : Light green     G : Green     L : Blue
W : White     Y : Yellow     SB : Sky blue     BR : Brown
O : Orange     GR : Gray     R : Red     P : Pink     V : Violet

BATTERY

FRONT-ECU

HEADLAMP
RELAY: LO

RELAY
BOX

INPUT SIGNAL

· HEADLAMP AUTOMATIC
  SHUTDOWN
· TAIL LAMP SWITCH

HEADLAMP
ASSEMBLY (LH)

HEADLAMP
ASSEMBLY (RH)

Headlamp Relay (Low-Beam) Circuit

SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) USING SWS MONITOR

54C-178

DIAGNOSIS PROCEDURE

Step 1. ECU check by using the SWS monitor.
Check that the power supply and earth lines to the 
column switch (column-ECU) and the front-ECU and 
the SWS communication lines are normal.

• Ignition switch: OFF

ECUS TO BE CHECKED

• COLUMN ECU

• FRONT ECU

OK: "OK" is displayed for all the items

Q: Is the check result normal?

"OK" is displayed for all the items : 

Go to Step 2.

"NG" is displayed on the "COLUMN ECU" menu. : 

Refer to Inspection Procedure A-2 
"Communication with the column switch 
(column-ECU) is not possible 

P.54C-30

."

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

Refer to Inspection Procedure A-4 
"Communication with the front-ECU is not 
possible 

P.54C-42

."

Step 2. Function diagnosis by using the SWS 
monitor.
Check the SWS communication signal, which are 
related to the low-beam headlamps.

<Selected item> LIGHTING - HEADLAMP LO

• Ignition switch: ON

• Lighting switch: HEAD

OK: Normal conditions displayed for all the 
items

Q: Is the check result normal?

Normal conditions are displayed for all the items. : 

Go to Step 3.

Normal condition is not displayed for item 00 or 03. 
: 

Refer to Inspection Procedure L-4 "The 
column switch (lighting and turn-signal lamp 
switch) signal is not received 

P.54C-267

."

Normal condition is not displayed for item No.30. : 

Refer to Inspection Procedure L-2 "The 
ignition switch (IG1) signal is not received 

P.54C-261

."

Normal condition is not displayed for item No.35. : 

Refer to Inspection Procedure H-6 "The 
headlamp automatic shutdown function 
does not work normally 

P.54C-183

."

Normal condition is not displayed for item No.70. : 

Replace the front-ECU.

Step 3. Connector check: A-10X front-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Repair the defective connector.

Item No. Item name

Normal condition

Item 00

HEADLAMP SW

ON

Item 03

PASSING SW

OFF

Item 30

IG SW(IG1)

ON

Item 35

HD AUTO-CUT

OFF

Item 70

FRONT ECU ACK NORMAL ACK

AC310572AB

Connector: A-10X

Relay box side

10

11

5

9 8 7 6

4 3

1

2

Battery