Mitsubishi Montero (2004+). Manual - part 822

INPUT SIGNAL PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-545

STEP 4. Replace the ECU.
(1) Replace the RV meter.
(2) If the RV meter works normally, it indicates that a correct 

signal is sent from the RV meter switch.

Q: Does the ETACS-ECU receive correct signals from the 

RV meter switch?
YES : No action is necessary and testing is complete.
NO :  Replace the ETACS-ECU. If the RV meter works 

normally, it indicates that a correct signal is sent from 
the RV meter switch.

INSPECTION PROCEDURE P-1: ETACS-ECU does not receive any signal from the key reminder 
switch.

Key Reminder Switch Input Circuit

AC204170

CONNECTOR : D-30

BC

AC204172

CONNECTOR : D-202

AF

INPUT SIGNAL PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-546

.

CIRCUIT OPERATION
The ETACS-ECU operates the following functions or 
systems according to signal from the key reminder 
switch:

• Ignition key reminder tone alarm function

• Keyless entry system

• Dome light dimming function

.

TECHNICAL DESCRIPTION (COMMENT)
If the signal is not normal, the functions or systems, 
which are described in "CIRCUIT OPERATION", do 
not work normally.

.

TROUBLESHOOTING HINTS

• The key reminder switch may be defective

• The ETACS-ECU may be defective

• The wiring harness or connectors may have 

loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B

STEP 1. Check key reminder switch connector D-202 for 
loose, corroded or damaged terminals, or terminals 
pushed back in the connector.
Q: Is key reminder switch connector D-202 in good 

condition?
YES : Go to Step 2.
NO :  Repair or replace the damaged component(s). Refer 

to GROUP 00E, Harness Connector Inspection 

P.00E-2

. If the functions, which are described in 

"CIRCUIT OPERATION", work normally, the input 
signal from the key reminder switch should be normal.

AC204174

CONNECTOR : D-224

D-224(B)

AG

AC204172

CONNECTOR: D-202

AK

HARNESS SIDE

4

5

3

1

6

7

2

INPUT SIGNAL PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-547

STEP 2. Check the key reminder switch.
Disconnect key reminder switch connector D-202. Then check 
continuity between terminals.

Q: Is the key reminder switch in good condition?

YES : Go to Step 3.
NO :  Replace the key reminder switch. If the functions, 

which are described in "CIRCUIT OPERATION", work 
normally, the input signal from the key reminder 
switch should be normal.

STEP 3. Check the ground circuit to the key reminder 
switch. Test at key reminder switch connector D-202.
(1) Disconnect key reminder switch connector D-202 and 

measure the resistance available at the wiring harness side 
of the connector.

(2) Measure the resistance value between terminal 4 and 

ground.

• The resistance should equal 2 ohms or less.

Q: Is the measured resistance 2 ohms or less?

YES : Go to Step 5.
NO :  Go to Step 4.

IGNITION KEY

TESTER 
CONNECTION

SPECIFIED 
CONDITION

Inserted

4 

− 6

Open circuit

Removed

4 

− 6

Less than 2 ohms

AC204172

CONNECTOR: D-202

AK

HARNESS SIDE

4

5

3

1

6

7

2

AC204172

CONNECTOR: D-202

AK

HARNESS SIDE

4

5

3

1

6

7

2

5 4 3

2

1

7 6

ACX01595AB

CONNECTOR D-202
(HARNESS SIDE)

INPUT SIGNAL PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-548

STEP 4. Check the wiring harness between key reminder 
switch connector D-202 (terminal 4) and ground.

NOTE: Also check joint connector D-30 for loose, corroded, or 
damaged terminals, or terminals pushed back in the connector. 
If joint connector D-30 is damaged, repair or replace the dam-
aged component(s) as described in GROUP 00E, Harness 
Connector Inspection 

P.00E-2

.

Q: Is the wiring harness between key reminder switch 

connector D-202 (terminal 4) and ground in good 
condition?
YES : No action is necessary and testing is complete.
NO :  The wiring harness may be damaged or the 

connector(s) may have loose, corroded or damaged 
terminals, or terminals pushed back in the connector. 
Repair the wiring harness as necessary. If the 
functions, which are described in "CIRCUIT 
OPERATION", work normally, the input signal from 
the key reminder switch should be normal.

STEP 5. Check ETACS-ECU connector D-224 for loose, 
corroded or damaged terminals, or terminals pushed back 
in the connector.
Q: Is ETACS-ECU connector D-224 in good condition?

YES : Go to Step 6.
NO :  Repair or replace the damaged component(s). Refer 

to GROUP 00E, Harness Connector Inspection 

P.00E-2

. If the functions, which are described in 

"CIRCUIT OPERATION", work normally, the input 
signal from the key reminder switch should be normal.

AC204172

CONNECTOR: D-202

AK

HARNESS SIDE

4

5

3

1

6

7

2

AC204170

CONNECTOR : D-30

AJ

9 10

8

6 7

31 32

30

29

18 19 20 21

5

4

2

1

3

27

26

24

23

25

12 13 14 15 16 17

28

11
22
33

AC204174

CONNECTOR : D-224

AD

D-224(B)

D-224(B)

HARNESS SIDE

21

23

24

22

32

3433

31

26

27

28

3029

38

39

40

36

37

25

35