Inspection Procedure 2

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 module, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.

Hands Free Cellular Phone System Circuit (Part 1):

Hands Free Cellular Phone System Circuit (Part 2):

FUNCTION
During the conversation with the hands free cellular phone system, the signal of speaker's voice is transmitted 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).

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.

NOTE: Also check intermediate connector C-133 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-133 is damaged, repair or replace the connector.

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.