Mitsubishi Colt Ralliart. Manual - part 408

SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) USING SWS MONITOR

54C-140

INSPECTION PROCEDURE J-2: 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, the headlamp relay 
(LO) or the ETACS-ECU may be defective. If the 
SWS monitor ECU check shows "NG", also check 
the headlamp backup circuit (from column switch 
connector terminal No.10 to ETACS-ECU connector 
terminal No.60) and repair if necessary.

POSSIBLE CAUSES

• Malfunction of the headlamp relay (LO)

• Malfunction of the column switch

• 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 
column switch (column-ECU) and the front-ECU and 
the SWS communication lines are normal.

• Ignition switch: OFF

ECU TO BE CHECKED

• COLUMN ECU

• ETACS ECU

OK: "OK" are displayed for all the items

Q: Are the check results normal?

"OK" are 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 column switch 
(column-ECU) is not possible 

P.54C-37

."

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

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

P.54C-41

."

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

ETACS-ECU

HEADLAMP
RELAY (LO)

HAEDLAMP

FUSIBLE
LINK

1

HEADLAMP SWITCH

INPUT SIGNAL

J/B SIDE

Headlamp Relay (Low-Beam) Circuit

Main

Index

Group

TOC

SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) USING SWS MONITOR

54C-141

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 are displayed for all 
the items

Q: Are the check results normal?

Normal conditions are displayed for all the items. : 

Go to Step 3.

Normal condition is not displayed for item No.00 or 
03. : 

Refer to inspection procedure N-4 "The 
column switch (lighting and turn-signal lamp 
switch) signal is not received 

P.54C-208

."

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

Refer to inspection procedure N-2 "The 
ignition switch (IG1) signal is not received 

P.54C-203

."

Step 3. Connector check: B-123 headlamp relay 
(LO) connector

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Repair the defective connector.

Step 4. Check the headlamp relay (LO).
Refer to GROUP 54A 

− Headlamp 

P.54A-74

.

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Replace the headlamp relay (LO).

Step 5. Voltage measurement at B-123 headlamp 
relay (LO) connector.

(1) Remove the headlamp relay (LO), and measure 

at the junction block side.

(2) Voltage between B-123 headlamp relay (LO) 

connector terminal Nos.1, 3 and body earth

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Go to Step 6.

Item No.

Item name

Normal 
condition

Item 00

HEADLAMP SW

ON

Item 03

PASSING SW

OFF

Item 30

IG SW(IG1)

ON

AC313870 AD

Connector: B-123

Junction Block (Front view)

Harness side

AC313870 AD

Connector: B-123

Junction Block (Front view)

Harness side

AC313972AV

Connector B-123 

(Harness side)

Main

Index

Group

TOC

SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) USING SWS MONITOR

54C-142

Step 6. Check the wiring harness between B-123 
headlamp relay (LO) connector terminal Nos.1, 3 
and the fusible link (1).

NOTE: 

Prior to the wiring harness inspection, check the 
junction block connector B-108, and repair if neces-
sary.

• Check the power supply line from the fusible link 

(1) for open circuit.

Q: Is the check result normal?

YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00 

− How to 

use Troubleshooting/inspection Service 
Points 

− How to Cope with Intermittent 

Malfunction 

P.00-13

).

NO : 

Repair the wiring harness.

Step 7. Connector check: B-134 ETACS-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 8.

NO : 

Repair the defective connector.

Step 8. 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 

use Troubleshooting/inspection Service 
Points 

− How to Cope with Intermittent 

Malfunction 

P.00-13

).

NO : 

Replace the ETACS-ECU.

AC313870 AD

Connector: B-123

Junction Block (Front view)

Harness side

AC313870

Connector: B-108

BD

Junction block (Front view)

B-108(B)

Harness side

AC313872 AH

Connector: B-134

Harness side

Junction block (Rear view)

Main

Index

Group

TOC

SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) USING SWS MONITOR

54C-143

INSPECTION PROCEDURE J-3: 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 
headlamp switch input circuit, the headlamp relay 
(HI) or the ETACS-ECU may be defective.

POSSIBLE CAUSES

• Malfunction of the headlamp relay (HI)

• Malfunction of the column switch

• 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 
column switch (column-ECU) and the front-ECU and 
the SWS communication lines are normal.

• Ignition switch: OFF

ECU TO BE CHECKED

• COLUMN ECU

• ETACS ECU

OK: "OK" are displayed for all the items

Q: Are the check results normal?

"OK" are 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 column switch 
(column-ECU) is not possible 

P.54C-37

."

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

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

P.54C-41

."

J/B SIDE

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

Headlamp Relay (High-Beam) Circuit

ETACS-ECU

HEADLAMP
RELAY (HI)

HAEDLAMP

FUSIBLE
LINK

1

· HEADLAMP SWITCH

INPUT SIGNAL

· DIMMER SWITCH

Main

Index

Group

TOC