Mitsubishi Colt Ralliart. Manual - part 348

SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) NOT USING SWS MONITOR

54B-136

DIAGNOSIS PROCEDURE

Step 1. Pulse check
Check the input signal from the tail lamp switch.

OK: The M.U.T.-III sounds or the voltmeter 
needle fluctuates.

Q: Is the check result normal?

All the signals are received normally. : 

Go to Step 

2.

The ignition switch (IG1) signal is not received. : 

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

P.54B-202

."

The tail lamp switch signal is not received. : 

Refer 

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

P.54B-206

."

Step 2. Connector check: B-134 ETACS-ECU 
connector.

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Repair the defective connector.

Step 3. Voltage measurement at B-134 
ETACS-ECU connector.

(1) Remove the ETACS-ECU, and measure at the 

junction block side.

(2) Voltage between B-134 ETACS-ECU connector 

terminal No.16 and body earth

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Go to Step 4.

System switch

Check condition

Ignition switch (IG1)

When turned from ACC 
to ON

Tail lamp switch

When the lighting switch 
is turned to the TAIL 
position

AC313872 AH

Connector: B-134

Harness side

Junction block (Rear view)

AC313872 AH

Connector: B-134

Harness side

Junction block (Rear view)

AC313972

Connector B-134
 (Harness side)

AT

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SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) NOT USING SWS MONITOR

54B-137

Step 4. Check the wiring harness between B-134 
ETACS-ECU connector terminal No.16 and the 
fusible link (1).

NOTE: 

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

• 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 

use Troubleshooting/inspection Service 
Points 

− How to Cope with Intermittent 

Malfunction 

P.00-13

).

NO : 

Repair the wiring harness.

Step 5. 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 

use Troubleshooting/inspection Service 
Points 

− How to Cope with Intermittent 

Malfunction 

P.00-13

).

NO : 

Replace the ETACS-ECU.

AC313872 AH

Connector: B-134

Harness side

Junction block (Rear view)

AC313870

Connector: B-108

BD

Junction block (Front view)

B-108(B)

Harness side

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SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) NOT USING SWS MONITOR

54B-138

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

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

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Group

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SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) NOT USING SWS MONITOR

54B-139

DIAGNOSTIC PROCEDURE

Step 1. Pulse check
Check the input signal from the headlamp switch.

OK: The M.U.T.-III sounds or the voltmeter 
needle fluctuates.

Q: Are the check result normal?

All the signals are received normally. : 

Go to Step 

2.

The ignition switch (IG1) signal is not received. : 

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

P.54B-202

."

The headlamp switch signal is not received. : 

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

P.54B-206

."

Step 2. Connector check: B-123 headlamp relay 
(LO) connector

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Repair the defective connector.

Step 3. Check the headlamp relay (LO).
Refer to GROUP 54A 

− Headlamp 

P.54A-74

.

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Replace the headlamp relay (LO).

Step 4. 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 6.

NO : 

Go to Step 5.

System switch

Check condition

Ignition switch (IG1)

When turned from ACC 
to ON

Headlamp switch

When the lighting switch 
is turned to the HEAD 
position

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)

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