Mitsubishi Lancer (4A9 engine). Manual - part 179

MITSUBISHI MULTI COMMUNICATION SYSTEM (MMCS)

CHASSIS ELECTRICAL

54A-378

STEP 4. Check the wiring harness between C-144 
multivision display connector terminal No.14 and 
C-313 ETACS-ECU connector terminal No.1

• Check the power supply lines (battery power sup-

ply) for open circuit and short circuit.

NOTE: Prior to the wiring harness inspection, check 
intermediate connector C-31, C-128 and C-139, and 
repair if necessary.

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Repair the wiring harness.

STEP 5. Connector check: C-65 DC/DC converter 
connector

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Repair the defective connector.

STEP 6. Check the wiring harness between C-65 
DC/DC converter connector terminal No.8 and C-
128 intermediate connector terminal No.1.

• Check the signal lines for short circuit.

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Repair the wiring harness.

STEP 7. Connector check: C-142, C-143 
multivision display connector

Q: Is the check result normal?

YES : 

Go to Step 8.

NO : 

Repair or replace the damaged 
component(s).

STEP 8. Resistance measurement at C-142, C-
143, C-144 multivision display connector.
(1) Disconnect C-144 multivision display connector, 

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

(2) Check the continuity between terminal No.9 and 

body earth.

OK: Continuity exists (2 

Ω or less)

(3) Disconnect C-143 multivision display connector, 

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

(4) Check the continuity between terminal No.25 and 

body earth.

OK: Continuity exists (2 

Ω or less)

(5) Disconnect C-142 multivision display connector, 

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

(6) Check the continuity between terminal No.65 and 

body earth.

OK: Continuity exists (2 

Ω or less)

Q: Is the check result normal?

YES : 

Go to Step 10.

NO : 

Go to Step 9.

STEP 9. Check the wiring harness between C-144 
multivision display connector terminal No.9 or C-
143 multivision display connector terminal No.25 
or C-142 multivision display connector terminal 
No.65 and body earth.
NOTE: Prior to the wiring harness inspection, check 
intermediate connector C-133 and C-139, and repair 
if necessary.

• Check the earth wires for open circuit.

Q: Is the check result normal?

YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00 

− How to 

use Troubleshooting/inspection Service 
Points 

− How to Cope with Intermittent 

Malfunction ).

NO : 

Repair the wiring harness. 

STEP 10. Voltage measurement at C-144 
multivision display connector.
(1) Disconnect the connector, and measure at the 

wiring harness-side connector.

(2) Voltage between C-144 multivision display 

connector terminal No.17 and the body earth

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 17.

NO : 

Go to Step 11.

STEP 11. Check the wiring harness between C-
144 multivision display connector terminal No.17 
and fusible link (38) <Diesel> or (36) <Petrol>

• Check the power supply lines (battery supply) for 

open circuit and short circuit.

NOTE: Prior to the wiring harness inspection, check 
intermediate connector C-128, C-31 and C-139, 
ETACS-ECU connector C-311 and C-307, and repair 
if necessary.

Q: Is the check result normal?

YES : 

Go to Step 12.

NO : 

Repair the wiring harness.

MITSUBISHI MULTI COMMUNICATION SYSTEM (MMCS)

CHASSIS ELECTRICAL

54A-379

STEP 12. Voltage measurement at C-65 DC/DC 
converter connector.
(1) Disconnect C-65 DC/DC converter connector, 

and measure at the wiring harness side.

(2) Measure the voltage between terminal No.9 and 

body earth.

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 13.

NO : 

Go to Step 16.

STEP 13. Check the DC/DC converter.
Check the continuity of the DC/DC converter (Refer 
to ).

Q: Is the check result normal?

YES : 

Go to Step 14.

NO : 

Replace the DC/DC converter.

STEP 14. Connector check: C-128 intermediate 
connector

Q: Is the check result normal?

YES : 

Go to Step 15.

NO : 

Repair the defective connector.

STEP 15. Check the wiring harness between C-
128 intermediate connector terminal No.9 and C-
65 DC/DC converter terminal No.7.

• Check the power supply lines (battery supply) for 

open circuit and short circuit.

Q: Is the check result normal?

YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00 

− How to 

use Troubleshooting/inspection Service 
Points 

− How to Cope with Intermittent 

Malfunction ).

NO : 

Repair the wiring harness.

STEP 16. Check the wiring harness between DC/
DC converter connector terminal No.9 and 
fusible link (38) <Diesel> or (36) <Petrol>

• Check the power supply lines (battery supply) for 

open circuit and short circuit.

Q: Is the check result normal?

YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00 

− How to 

use Troubleshooting/inspection Service 
Points 

− How to Cope with Intermittent 

Malfunction ).

NO : 

Repair the wiring harness.

STEP 17. Voltage measurement at C-143 
multivision display connector.
(1) Disconnect the connector, and measure at the 

wiring harness-side connector.

(2) Voltage between C-143 multivision display 

connector terminal No.21 and the body earth

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 19.

NO : 

Go to Step 18.

STEP 18. Check the wiring harness between C-
143 multivision display connector terminal No. 21 
and C-128 intermediate connector terminal No.9

• Check the power supply lines (battery supply) for 

open circuit or short circuit.

NOTE: Prior to the wiring harness inspection, check 
intermediate connector C-133, and repair if neces-
sary.

Q: Is the check result normal?

YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00 

− How to 

use Troubleshooting/inspection Service 
Points 

− How to Cope with Intermittent 

Malfunction ).

NO : 

Repair the wiring harness.

STEP 19. Retest the system
Check if the multivision display power is turned ON.

Q: Is the check result normal?

YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00 

− How to 

use Troubleshooting/inspection Service 
Points 

− How to Cope with Intermittent 

Malfunction ).

NO : 

Replace the multivision display.

MITSUBISHI MULTI COMMUNICATION SYSTEM (MMCS)

CHASSIS ELECTRICAL

54A-380

Inspection Procedure 2: No sound is heard. <Vehicles without audio amplifier>

CAUTION

Whenever the multivision display is replaced, 
ensure that the power supply circuit and the 
earthing circuit are normal. (Check that the volt-
age is 10 V or more.)

COMMENTS ON TROUBLE SYMPTOM
If the sound is not output, the multivision display may 
have a problem. In addition, if any of the speakers is 
short-circuited, the protection circuit inside the multi-
vision display disables all the speakers to sound. 
Therefore, if all the speakers do not output sound, 
the speaker circuit may be shorted or the speaker 
may be defective. In some cases, the sound is output 
depending on sources, thus use the music server, 
radio, CD/DVD, and others to check if the sound is 
output. Also, the option coding information may be 
inconsistent.
PROBABLE CAUSES

• Malfunction of speaker or tweeter

• Malfunction of multivision display

• Option coding information inconsistency

• Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. Check the multivision display operation.

Q: Check the sources from which the sound is not 

output.

AC701094

Connector: C-144 <LHD>

BJ

C-144 (GR)

AC701122 CL

Connector: C-144 <RHD>

C-144 (GR)

AC612730

Connectors: E-02, E-12

AD

E-02 (B)

E-12

AC612731

Connectors: E-04, E-10

AD

E-04 (B)

E-10

AC612733

Connector: E-21

AB

AC612732

Connector: E-22

AB

MITSUBISHI MULTI COMMUNICATION SYSTEM (MMCS)

CHASSIS ELECTRICAL

54A-381

No sound only from radio : 

Perform Inspection 

Procedure 6 "The FM/MW/LM radio 
broadcasting can not be received."(Refer to 
.)

No sound only when the CD is played : 

Perform 

Inspection Procedure 8 "CD/DVD cannot be 
played." (Refer to .) 

No sound only when the DVD is played : 

Perform 

Inspection Procedure 8 "CD/DVD cannot be 
Played." (Refer to .) Or, perform Inspection 
Procedure 9 "Image of a DVD is Played, but 
no Sound is Played."(Refer to .)

Only the sound that is relevant to the hands free 
function and USB adapter function is not output. 
<Vehicles with hands free ECU> : 

Diagnose the 

hands free ECU. (Refer to .) 

Only the sound relevant to USB adapter is not 
output. <Vehicles with USB box> : 

Troubleshoot 

the USB box. (Refer to .) 

No sound only when the music server is used : 

Go 

to Step 8.

No sound from any of the sources <except 
vehicles for RUSSIA> : 

Go to Step 8.

No sound from any of the sources <vehicles for 
RUSSIA> : 

Go to Step 2.

STEP 2. ETACS-ECU coding data check
(1) Operate the M.U.T.-III to read the ETACS-ECU 

option coding information (Refer to GROUP 00 

− 

Coding Table ).

(2) Check that the "Number of speaker" is set to "6 

speakers or 4 speakers".

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Operate the M.U.T.-III to set the option 
coding "Number of speaker" to "6 
speakers", and check the trouble symptom.

STEP 3. Check the MMCS service mode, CAN 
communication confirmation and coding data
(1) Display the CAN communication confirmation 

and coding data for the MMCS service mode. 
(Refer to )

(2) Check if "6SPEAKER(2TWEETER) or 

4SPEAKER" is displayed as the number of 
installed speakers.

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Go to Step 5.

STEP 4. Check the service data log for the MMCS 
service mode.
Display the service data log for the MMCS service 
mode and check if the service data log for the SP 
(speaker) is displayed. (Refer to )

Q: Is the service data log for the SP (speaker) 

displayed?
YES : 

Go to Step 5.

NO : 

Go to Step 8.

STEP 5. M.U.T.-III CAN bus diagnostics
Use the M.U.T.-III to diagnose the CAN bus lines.

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Repair the CAN bus line.

STEP 6. Check whether the diagnosis code is set.
Check if the diagnosis code is set to the CAN box 
unit.
(1) Turn the ignition switch from "LOCK" (OFF) 

position to "ON" position.

(2) Check if diagnosis code is set.

Q: Is the diagnosis code set?

YES : 

Troubleshoot the MMCS (Refer to ).

NO : 

Go to Step 7.

STEP 7. M.U.T.-III other system diagnosis code
Check if the diagnosis code is set to the ETACS-
ECU.

Q: Is the diagnosis code set?

YES : 

Diagnose the ETACS-ECU (Refer to 

GROUP 54A 

− ETACS-ECU − 

Troubleshooting ).

NO : 

Go to Step 8.

STEP 8. Check the service data log for the MMCS 
service mode.
(1) Display the service data log for the MMCS 

service mode. (Refer to )

(2) Check if the service data log for drive and HDD is 

displayed.

Q: Is the service data log displayed?