Mitsubishi Grandis. Manual - part 271

INPUT SIGNAL PROCEDURES

SMART WIRING SYSTEM (SWS) USING SWS MONITOR

54C-546

Inspection Procedure Q-20: The front passenger's seat belt switch signal is not received. <RH drive 
vehicles>

CAUTION

Whenever the ECU is replaced, ensure that the 
input signal circuit is normal.

COMMENTS ON TROUBLE SYMPTOM

Input signal from the passenger’s seat belt switch is 
used to operate the central door locking function. If 
the signal is abnormal, the central door locking 
function will not work normally.

POSSIBLE CAUSES

• Malfunction of the passenger’s seat belt switch

• Malfunction of the seat occupancy sensor

• Malfunction of the ETACS-ECU

• Damaged harness wires and connectors

DIAGNOSTIC PROCEDURE

Step 1. Connector check: D-23 seat belt switch 
(LH) connector

Q: Is the check result normal?

ETACS-
ECU

SEAT
BELT
SWITCH
(LH)

SEAT
OCCUPANCY
SENSOR

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

Passenger's Seat Belt Switch Input Circuit <RHD>

AC312058

AD

Connector: D-23 <RHD>

INPUT SIGNAL PROCEDURES

SMART WIRING SYSTEM (SWS) USING SWS MONITOR

54C-547

YES : 

Go to Step 2.

NO : 

Repair the defective connector.

Step 2. Check the seat belt switch (LH).

Refer to GROUP 52A 

− Front seat belt 

P.52A-36

.

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Replace the inner seat belt (front 
passenger's side).

Step 3. Connector check: D-23-1 seat occupancy 
sensor connector

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Repair the defective connector.

Step 4. Check the seat occupancy sensor.

Refer to GROUP 52A 

− Front seat 

P.52A-22

.

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Replace the seat occupancy sensor.

Step 5. Resistance measurement at the D-23-1 
seat occupancy sensor connector.

(1) Disconnect the connector, and measure at the 

wiring harness side.

(2) Resistance between D-23-1 seat occupancy 

sensor connector terminal No.3 and body earth

OK: 2 

Ω or less

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Go to Step 6.

Step 6. Check the wiring harness between D-23-1 
seat occupancy sensor connector terminal No.3 
and body earth.

• Check the earth wires for open circuit.

Q: Is the check result normal?

YES : 

Replace the inner seat belt (front 

passenger's side).

NO : 

Repair the wiring harness.

Step 7. Connector check: C-220 ETACS-ECU 
connector

Q: Is the check result normal?

AC313233

Connector: D-23-1

AC

Harness side

<RHD>

AC313233

Connector: D-23-1

AC

Harness side

<RHD>

AC301541IC

Connector D-23-1
(Harness side)

AC313233

Connector: D-23-1

AC

Harness side

<RHD>

AC312047

Connector: C-220

Junction block (Rear view)

AC

<RHD>

Harness side

INPUT SIGNAL PROCEDURES

SMART WIRING SYSTEM (SWS) USING SWS MONITOR

54C-548

YES : 

Go to Step 8.

NO : 

Repair the defective connector.

Step 8. Check the wiring harness from D-23-1 
seat occupancy sensor connector terminal No.1 
to C-220 ETACS-ECU connector terminal No.29.

NOTE: 

Prior to the wiring harness inspection, check 
intermediate connector C-16, and repair if necessary.

• Check the input line for open circuit.

Q: Is the check result normal?

YES : 

Go to Step 9.

NO : 

Repair the wiring harness or replace the 
inner seat belt (front passenger's side).

Step 9. ETACS switch data by using the SWS 
monitor

Check the input signal from the front passenger's 
seat belt switch.

• Ignition switch: ON

• Passenger’s seat belt switch: ON (Unfastened)

• Seat occupancy sensor: ON (Seat occupied)

Check that the MUT-III displays normal condition 
when the condition above is changed to the condition 
below.

• Passenger’s seat belt switch: OFF (seat belt 

fastened) or seat occupancy sensor: OFF (seat 
not occupied)

OK: Normal condition is displayed.

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.

AC312047

Connector: C-220

Junction block (Rear view)

AC

<RHD>

Harness side

AC313233

Connector: D-23-1

AC

Harness side

<RHD>

AC312043

Connector: C-16 <RHD>

AH

9

21

33

35

24

12

3 4

7

8

5 6

39

28

41

30

18

4243

31

1920

32

40

29

1617

38

27

15

37

36

26

14

13

25

2

1

34

23

11

10

22

Item No.

Item name

Normal 
condition

Item 43

As.SeatBeltSW

ON

Item No.

Item name

Normal 
condition

Item 43

As.SeatBeltSW

OFF

INPUT SIGNAL PROCEDURES

SMART WIRING SYSTEM (SWS) USING SWS MONITOR

54C-549

Inspection Procedure Q-21: Signal is not received from the remote controlled mirror switch 
(folding/unfolding switch).

CAUTION

Whenever the ECU is replaced, ensure that the 
input signal circuit is normal.

COMMENTS ON TROUBLE SYMPTOM

The electric-folding door mirrors work in accordance 
with the input signal from the remote controlled 
mirror switch. If the input signal is abnormal, the door 
mirrors will not work normally.

POSSIBLE CAUSES

• Malfunction of the remote controlled mirror switch

• Malfunction of the ETACS-ECU

• Damaged harness wires and connectors

ETACS-
ECU

REMOTE
CONTROLLED 
MIRROR SWITCH

<RHD>

<LHD>

Remote Controlled Mirror Switch Input Circuit

FOLD 
SWITCH

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