Mitsubishi Grandis. Manual - part 24

SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) NOT USING SWS MONITOR

54B-93

Step 2. Pulse check
Check the input signals below, which are related to 
the lamp reminder buzzer function.

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 

3.

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 driver's door switch signal is not received. : 

Refer to inspection procedure Q-5 "The 
driver’s door switch signal is not received 

P.54B-434

 <LH drive vehicles> or 

P.54B-436

 <RH drive vehicles>."

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

."

The headlamp 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 3. Retest the system.
The lamp reminder buzzer function should 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

Driver's door switch

When the driver's door is 
opened

Tail lamp switch

When the lighting switch 
is turned to the TAIL 
position

Headlamp switch

When the lighting switch 
is turned to the 
HEADLAMP position

SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) NOT USING SWS MONITOR

54B-94

INSPECTION PROCEDURE B-2:  Seat belt warning buzzer function does not work normally.

CAUTION

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

COMMENTS ON TROUBLE SYMPTOM

If the function does not work normally, the input 
circuit system from the switches or the ETACS-ECU 
may be defective (refer to "CIRCUIT OPERATION").

POSSIBLE CAUSES

• Malfunction of the ETACS-ECU

• Malfunction of the driver's seat belt switch

• Malfunction of the passenger's seat belt switch

• 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 buzzer does not function normally.

Q: Which seat belt switch does not activate the seat 

belt warning buzzer?

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 buzzer function.

• 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?

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.54B-498

 <LH drive vehicles> or 

P.54B-501

 <RH drive vehicles>."

Seat Belt Warning Buzzer 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-95

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

• 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.54B-504

 <LH drive vehicles> 

or 

P.54B-507

 <RH drive vehicles>."

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

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 buzzer function 
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.

Inspection Procedure B-3: Door-ajar warning buzzer function does not work normally.

CAUTION

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

COMMENTS ON TROUBLE SYMPTOM

The ETACS-ECU operates this function in 
accordance with the input signals below.

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.

Door-Ajar Warning Buzzer Function

ETACS-
ECU

SPEED SIGNAL

COMBINATION
METER

CAN COMMUNICATION LINE
(CAN_L LINE)

CAN COMMUNICATION LINE
(CAN_H LINE)

INPUT SIGNAL

INPUT SIGNAL

· DOOR SWITCHES
· IGNITION SWITCH (IG1)
· TAILGATE SWITCH

SYMPTOM PROCEDURES

SMART WIRING SYSTEM (SWS) NOT USING SWS MONITOR

54B-96

• Ignition switch (IG1)

• All of the door switches

• Vehicle speed signal

If this function does not work normally, these input 
signal circuit(s) or the ETACS-ECU may be 
defective. Note that this function can be 
disabled/enabled by the customize function (default 
setting; enabled). In order to change the setting, the 
SWS monitor is required.

POSSIBLE CAUSES

• Malfunction of the door switches

• Malfunction of the ETACS-ECU

• Damaged harness wires and connectors

DIAGNOSTIC PROCEDURE

Step 1. Check the power supply circuit.
When the ignition switch is turned to the LOCK 
(OFF) position, check if the hazard warning lamps 
illuminate.

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Refer to inspection procedure A-2 "Check 
the ETACS-ECU battery power supply 
circuit 

P.54B-87

."

Step 2. Pulse check
Check the input signals below, which are related to 
the door-ajar warning buzzer function.

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 

3.

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

.

All the door switch signals are not received. : 

Refer to inspection procedure Q-14 "All the 
door switch signals are not received" 

P.54C-505

.

The vehicle speed signal is not received. : 

Refer to 

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

P.54B-529

.

System switch

Check conditions

Ignition switch (IG1)

When turned from ACC 
to ON

Driver's door switch

Driver's door is opened 
while all the other doors 
are closed.

Passenger’s door switch Passenger's door is 

opened while all the 
other doors are closed.

Rear door (RH) switch

Rear door (RH) is 
opened while all the 
other doors are closed

Rear door (LH) switch

Rear door (LH) door is 
opened while all the 
other doors are closed

Tailgate switch

TAilgate is opened while 
all the other doors are 
closed

Vehicle speed signal

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