Mitsubishi Montero (2004+). Manual — part 577

RV METER

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CHASSIS ELECTRICAL

54A-277

TECHNICAL DESCRIPTION (COMMENT)
If there is a problem on the picture display of RV
meter even though the function of A/C operates nor-
mally, it may be an abnormality on the M-BUS com-
munication line. When there is a problem on the
function itself, the abnormality of A/C-ECU is consid-
ered to be the cause.

.

TROUBLESHOOTING HINTS

• Malfunction of the RV meter

• Damaged harness wires and connectors

.

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 the communication and connection of the
service function (M-BUS).
(1) Press the adjusting switch with the ignition switch at the

"LOCK" (OFF) position. Then while keeping the switch on
the pressed condition, turn the ignition switch to " ACC"
position.

(2) When the adjusting switch is continuously pressed for more

than five seconds, the reception sound (pip sound) is heard
and at the same time the service function is activated to
display the service mode screen.

(3) Check the communication and connection

P.54A-238

.

Q: Which of the following M-BUS is indicated?

" E1 " (Communication error) : Go to Step 2.
" E2 " (Open circuit or not connected) : Go to Step 3.
OK : Go to Step 4.

RV METER

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CHASSIS ELECTRICAL

54A-278

STEP 2. Check the RV meter and A/C-ECU circuit by
backprobing.
(1) Do not disconnect RV meter connector D-08.
(2) ignition switch "ACC" position.
(3) Measure the voltage (waveform) between terminal 9 and

ground using an oscilloscope by backprobing.

(4) Measure the voltage (waveform) between terminal 10 and

ground by backprobing.

(5) Measure the voltage (waveform) between terminal 19 and

ground by backprobing.

Q: Is the measured voltage Hi = 4 to 5 volts and Lo = 0 to 1

volt?
YES : Replace the RV meter display.
No : Go to Step 5.

AC204738

20

19

18

17

7

6

15

14

4

3

11 12 13

5

1

9 10

2

16

8

AC204738 DV

HARNESS SIDE: D-08

AC204738 DW

HARNESS SIDE: D-08

20

19

18

17

7

6

15

14

4

3

11 12 13

5

1

9 10

2

16

8

AC204738 DX

HARNESS SIDE: D-08

20

19

18

17

7

6

15

14

4

3

11 12 13

5

1

9 10

2

16

8

RV METER

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CHASSIS ELECTRICAL

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STEP 3. Check the harness wires between RV meter
connector D-08 (terminal 9 and 10 and 19) and A/C-ECU
connector D-23 (terminal 16 and 17 and 6).

Q: Are harness wires between RV meter connector D-08

(terminal 9 and 10 and 19) and A/C-ECU connector D-23
(terminal 16 and 17 and 6) in good condition?
YES : There is no action to be taken.
NO : Repair or replace them. Refer to GROUP 00E,

Harness Connector Inspection

P.00E-2

.

STEP 4. Using scan tool MB991958, read the A/C
diagnostic trouble code.

CAUTION

To Prevent to damage to scan toll MB991958, always turn
the ignition switch to "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch "ON" position.
(3) Read the A/C diagnostic trouble code.
Q: Is the A/C diagnostic trouble code set?

YES : Carry out troubleshooting of the A/C.
NO : There is no action to be taken.

AC204188

D-08(B)

1

3

4

2

12

1413

11

6

7

8

10 9

18

19

20

16

17

5

15

AC204188

CONNECTORS: D-08, D-23

BU

HARNESS SIDE

HARNESS SIDE

D-08(B)

D-23(B)

D-23(B)

1

3

4

2

12

1413

11

6

7

8

10 9

18

19

20

16

17

5

15

AC307591 AB

MB991911

DATA LINK

CONNECTOR

MB991824

MB991827

RV METER

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CHASSIS ELECTRICAL

54A-280

STEP 5. Check the A/C-ECU by backprobing.

(1) Do not disconnect A/C-ECU connector D-23.
(2) ignition switch "ACC" position.
(3) Measure the voltage (waveform) between terminal 6 and

ground using an oscilloscope by backprobing.

(4) Measure the voltage (waveform) between terminal 16 and

ground by backprobing.

(5) Measure the voltage (waveform) between terminal 17 and

ground by backprobing.

Q: Is the measured voltage Hi = 4 to 5 volts and Lo = 0 to 1

volt?
YES : Go to Step 6.
NO : Replace the A/C-ECU.

STEP 6. Recheck for malfunction.
Q: Is a malfunction eliminated?

YES : If no malfunctions are not found in all steps, an

intermittent malfunction is suspected. Refer to
GROUP 00, How to Use Troubleshooting/Inspection
Service Points

− How to Cope with Intermittent

Malfunction

P.00-6

.

NO : Replace the RV meter.

AC204738 DY

HARNESS SIDE: D-23

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19

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17

7

6

15

14

4

3

11 12 13

5

1

9 10

2

16

8

AC204738 DZ

HARNESS SIDE: D-23

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17

7

6

15

14

4

3

11 12 13

5

1

9 10

2

16

8

AC204738 EA

HARNESS SIDE: D-23

20

19

18

17

7

6

15

14

4

3

11 12 13

5

1

9 10

2

16

8