Mitsubishi Lancer Evolution IX. Manual - part 230

SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) USING SWS MONITOR

54C-179

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 Nos.3, 4 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 Nos.3, 4 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 low-beam headlamps illuminate nor-
mally.

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

AC301541 DC

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-180

INSPECTION PROCEDURE H-4: The high-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 high-beam headlamps do not illuminate, the 
dimmer 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

TAIL LAMP
RELAY: HI

RELAY
BOX

INPUT SIGNAL

· HEADLAMP AUTOMATIC
  SHUTDOWN
· TAIL LAMP SWITCH

· COMBINATION METER
· HEADLAMP (LH)

HEADLAMP (RH)

Headlamp Relay (High-Beam) Circuit

SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) USING SWS MONITOR

54C-181

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 high-beam headlamps.

<Selected item> LIGHTING - HEADLAMP HI

• Ignition switch: ON

• Lighting switch: HEAD

• Dimmer switch: from OFF to ON, and then to 

OFF again

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, 02 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

Item 02

DIMMER SW

from OFF to ON, and 
then to OFF again ("ON" 
should be displayed 
when the dimmer switch 
is operated)

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-182

Step 3. Retest the system.
Check that the high-beam headlamps illuminate nor-
mally.

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.

INSPECTION PROCEDURE H-5: The high-beam and low-beam headlamps do not illuminate when the 
passing switch is operated.

CAUTION

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

COMMENTS ON TROUBLE SYMPTOM

If the low-beam and high-beam headlamps are nor-
mal, the passing switch input signal 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

DIAGNOSIS PROCEDURE

Step 1. Check the operation of the headlamps.
Check that the low-beam and high-beam headlamps 
illuminate normally.

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Refer to Inspection Procedure H-3 "The 
low-beam headlamps do not illuminate 
normally 

P.54C-177

." And refer to 

Inspection Procedure H-4 "The high-beam 
headlamps do not illuminate normally 

P.54C-180

."

Step 2. Check the SWS monitor data list.
Check the ETACS-ECU signals which are related to 
the headlamps.

<Selected item> COLUMN ECU

• Passing lamp switch: ON

OK: Normal condition is displayed.

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

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

P.54C-267

."

Step 3. Retest the system.
When the passing switch is turned on, check if the 
headlamps 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.

Item No.

Item name

Normal condition

Item 03

PASSING SW

ON