Mitsubishi Evolution X. Manual - part 1034

HANDS-FREE CELLULAR PHONE SYSTEM

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CHASSIS ELECTRICAL

54A-497

STEP 14. Temporarily replace the hands free module, and 
check the trouble symptom.
Check that the normal conversation is possible with the hands 
free cellular phone system.
Q: Is the normal conversation possible with the hands free 

cellular phone system?
YES : Replace the hands free module.
NO :  Replace the radio and CD player <vehicles without 

MMCS> or multivision display <vehicles with MMCS>.

Inspection Procedure 2: During the conversation with the hands free cellular phone system, the 
speaker’s voice cannot be heard by the other party.

CAUTION

Before replacing the ECU, ensure that the power supply circuit, the ground circuit and the communi-
cation circuit are normal.

Hands Free Cellular Phone System Circuit

MICROPHONE
UNIT

HANDS 
FREE MODULE

HANDS-FREE CELLULAR PHONE SYSTEM

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CHASSIS ELECTRICAL

54A-498

.

FUNCTION

During the conversation with the hands free cellular 
phone system, the signal of speaker's voice is trans-
mitted from the microphone unit to the hands free 
module. Then the signal is transmitted from the 
hands free module to the cellular phone.

.

TROUBLE JUDGMENT CONDITIONS

During the conversation with the hands free cellular 
phone system, if the speaker's voice cannot be 
heard by the other party, the hands free module or 
microphone unit may be defective.

.

TROUBLESHOOTING HINTS

• The hands free module may be defective.

• The microphone unit may be defective.

• Damaged harness wires and connectors

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• MB992006: Extra Fine Probe

STEP 1. Check the cellular phone.
Check that the cellular phone can be used normally as a unit.
Q: Is it possible to use the cellular phone normally?

YES : Go to Step 2.
NO :  Repair or replace the cellular phone.

STEP 2. Check hands free module connector C-11 and 
microphone unit connector D-04 for loose, corroded or 
damaged terminals, or terminals pushed back in the 
connector.
Q: Are hands-free module connector C-11 and microphone 

unit connector D-04 in good condition?
YES : Go to Step 3.
NO :  Repair or replace the damaged component(s). Refer 

to GROUP 00E, Harness Connector Inspection 

P.00E-2

.

AC708951BT

Connector: C-11

AC708954 AT

Connector: D-04

HANDS-FREE CELLULAR PHONE SYSTEM

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CHASSIS ELECTRICAL

54A-499

STEP 3. Check the wiring harness between hands free 
module connector C-11 and microphone unit connector 
D-04.

• Check the communication lines for open circuit and short 

circuit.

(1) Disconnect hands free module connector C-11 and 

microphone unit connector D-04, and check the wiring 
harness.

(2) Check the wiring harness between hands-free module 

connector C-11 (terminal 24) and microphone unit 
connector D-04 (terminal 2)

(3) Check the wiring harness between hands-free module 

connector C-11 (terminal 23) and microphone unit 
connector D-04 (terminal 1)

Q: Is the wiring harness between hands free module 

connector C-11 and microphone unit connector D-04 in 
good condition?
YES : Go to Step 4.
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.

STEP 4. Temporarily replace the microphone unit, and 
check the trouble symptom.
Check that the normal conversation is possible with the 
hands-free system.
Q: Is the normal conversation possible with the hands free 

system?
YES : Replace the microphone unit.
NO :  Replace the hands free module.

HANDS-FREE CELLULAR PHONE SYSTEM

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CHASSIS ELECTRICAL

54A-500

Inspection Procedure 3: During the conversation with the hands free cellular phone system, the voice 
of other party cannot be heard.

.

FUNCTION

During the conversation with the hands free cellular 
phone system, the voice signal of other party is 
transmitted from the cellular phone to the hands free 
module. Then, the signal is transmitted from the 
hands free module to the radio and CD player <vehi-
cles without MMCS> or multivision display <vehicles 
with MMCS>, and then output from the speaker.

.

TROUBLE JUDGMENT CONDITIONS

During the conversation with the hands free cellular 
phone system, if the voice of other party cannot be 
heard, the hands free module, or the radio and CD 
player <vehicles without MMCS> or multivision dis-
play <vehicles with MMCS> may be defective.

.

TROUBLESHOOTING HINTS

• The hands free module may be defective.

• The radio and CD player <vehicles without 

MMCS> or multivision display <vehicles with 
MMCS> may be defective.

DIAGNOSIS

STEP 1. Check the cellular phone.
Check that the cellular phone can be used normally as a unit.
Q: Is it possible to use the cellular phone normally?

YES : Go to Step 2.
NO :  Repair or replace the cellular phone.

STEP 2. Check the radio and CD player <vehicles without 
MMCS> or multivision display <vehicles with MMCS>.
Check that the sound of radio and CD player <vehicles without 
MMCS> or multivision display <vehicles with MMCS> is output 
normally from the speaker.
Q: Is the sound of radio and CD player <vehicles without 

MMCS> or multivision display <vehicles with MMCS> 
output normally from the speaker?
YES : Replace the hands free module.
NO :  Diagnose the radio and CD player <vehicles without 

MMCS> or multivision display <vehicles with MMCS> 
(Refer to 

P.54A-317

 <vehicles without MMCS> or 

P.54A-408

 <vehicles with MMCS>).