Mitsubishi Grandis. Manual - part 68

SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) NOT USING SWS MONITOR

54B-269

Step 7. Retest the system.

Check that the ignition key cylinder illumination lamp 
illuminates/extinguishes 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 ETACS-ECU.

SEAT BELT WARNING LAMP

Inspection Procedure L-1: The seat belt warning lamp does not flash normally.

CAUTION

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

COMMENTS ON TROUBLE SYMPTOM

The ETACS-ECU flashes the seat belt warning lamp 
in accordance with the input signal from the ignition 
switch (IG1).
If it does not flash normally, these input signal 
circuit(s) or the ETACS-ECU may be defective.

POSSIBLE CAUSES

• Malfunction of the ETACS-ECU

• Damaged harness wires and connectors

DIAGNOSTIC PROCEDURE

Step 1. MUT-III diagnosis code
When the ignition switch is turned to the LOCK 
(OFF) position, check that the ETACS-ECU does not 
set the diagnosis code.

Q: Is the diagnosis code set?

YES : 

Refer to diagnosis code chart 

P.54B-29

.

NO : 

Go to Step 2.

Step 2. Check the seat belt switch, where the seat 
belt warning lamp does not function normally.

Q: Which seat belt switch does not activate the seat 

belt warning lamp?
Driver's seat belt : 

Go to Step 3

Passenger's seat belt : 

Go to Step 4.

Step 3. Pulse check
Check the input signals, which are related to the seat 
belt warning lamp.

• Ignition switch: ON

• Driver’s seat belt switch: ON

OK: The MUT-III sounds or the voltmeter 
needle fluctuates.

Q: Are the check result normal?

Seat Belt Warning Lamp Function

ETACS-
ECU

· SPEED SIGNAL
· DRIVER'S SEAT BELT SWITCH

COMBINATION
METER

CAN COMMUNICATION LINE
(CAN_L LINE)

CAN COMMUNICATION LINE
(CAN_H LINE)

INPUT SIGNAL

INPUT SIGNAL

· IGNITION SWITCH (IG1)
· PASSENGER'S SEAT BELT SWITCH

System switch

Check condition

Ignition switch (IG1)

When turned from ACC 
to ON

Driver’s seat belt switch ON

SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) NOT USING SWS MONITOR

54B-270

All the signals are received normally. : 

Go to Step 

5.

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

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

P.54B-420

."

Driver’s seat belt switch signal is not received : 

Refer to inspection procedure Q-19 "The 
driver's seat belt switch signal is not 
received 

P.54C-537

 <LH drive vehicles> or 

P.54C-540

 <RH drive vehicles>."

Step 4. Pulse check
Check the input signals, which are related to the seat 
belt warning lamp.

• Ignition switch: ON

• Passenger’s seat belt switch and seat occupancy 

sensor: ON

OK: The MUT-III sounds or the voltmeter 
needle fluctuates.

Q: Are the check result normal?

All the signals are received normally. : 

Go to Step 

5.

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

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

P.54B-420

."

Passenger’s seat belt switch signal is not received 
: 

Refer to inspection procedure Q-20 "The 
front passenger's seat belt switch signal is 
not received 

P.54C-543

 <LH drive vehicles> 

or 

P.54C-546

 <RH drive vehicles>."

Step 5. Pulse check
Check the input signals below which are related to 
the seat belt warning lamp.

OK: The MUT-III sounds or the voltmeter 
needle fluctuates.

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Refer to inspection procedure Q-25 "The 
vehicle speed signal is not received 

P.54B-529

."

Step 6. Retest the system.
Check that the seat belt warning lamp work 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 ETACS-ECU.

System switch

Check condition

Ignition switch (IG1)

When turned from ACC 
to ON

Passenger’s seat belt 
switch and seat 
occupancy sensor

ON

System switch

Check condition

Vehicle speed signal

When the vehicle speed 
has reached 10 km/h or 
more.

SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) NOT USING SWS MONITOR

54B-271

HEADLAMP AND TAIL LAMP

Inspection Procedure M-1: The tail/stop lamps 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 all the tail/stop lamps do not illuminate, the tail 
lamp 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

DIAGNOSTIC PROCEDURE

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

OK: The MUT-III sounds or the voltmeter 
needle fluctuates.

Q: Is the check result normal?

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

RELAY
BOX

INPUT SIGNAL

· HEADLAMP AUTOMATIC 
  SHUTDOWN
· TAIL LAMP SWITCH

· REAR COMBINATION 
  LAMP (LH)

· LICENSE PLATE LAMP
· POSITION LAMP (LH)

· REAR COMBINATION 
  LAMP (RH)

· POSITION LAMP (RH)

Tail Lamp Relay Circuit

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

SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) NOT USING SWS MONITOR

54B-272

All the signals are received normally. : 

Go to Step 

2.

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

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

P.54B-420

."

The tail lamp switch signal is not received. : 

Refer 

to inspection procedure Q-6 "The column 
switch (lighting and turn-signal lamp and 
headlamp washer switch) signal is not 
received 

P.54B-438

."

Step 2. Connector check: A-14X 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-14X front-ECU 
connector.

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

box side.

(2) Voltage between A-14X front-ECU connector 

terminal No.5 and body earth

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Go to Step 4.

Step 4. Check the wiring harness between A-14X 
front-ECU connector terminal No.5 and the 
fusible link (26).

• 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 5. Retest the system.
Check that the tail/stop 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.

AC311521AB

Connector: A-14X

Relay box side

AC311521AB

Connector: A-14X

Relay box side

AC310507CE

Connector A-14X 
(Relay box side)

AC311521AB

Connector: A-14X

Relay box side