Inspection Procedure 7

INSPECTION PROCEDURE 7: Check The Hands Free Module Power Supply Circuit.

CAUTION: Before replacing the module, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.

Hands Free Module Power Supply Circuit:

CIRCUIT OPERATION
The power supply to the hands free module is provided by the fusible link (36).

TECHNICAL DESCRIPTION (COMMENT)
If the hands free cellular phone system don't work, power supply and ground system to the hands free module, or the hands free module itself may be defective.

TROUBLESHOOTING HINTS
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
- The hands free module may be defective

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe

STEP 1. Check hands free module connector C-11 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is hands free module connector C-11 in good condition?

YES : Go to Step 2.

NO : Repair or replace the damaged component.

STEP 2. Check the ground circuit to the hands free module. Measure the resistance at hands free module connector C-11.

1. Disconnect hands-free module connector C-11, and measure at the wiring harness side.







2. Measure the resistance value between terminal 15 and ground.

OK: The resistance should be 2 ohms or less.

Q: Is the measured resistance 2 ohms or less?

YES : Go to Step 4.

NO : Go to Step 3.

STEP 3. Check the wiring harness between hands-free module connector C-11 (terminal 15) and ground.

- Check the ground wires for open circuit.

Q: Is the wiring harness between hands free module connector C-11 (terminal 15) and ground in good condition?

YES : Replace the hands free module. The system should communicate with the hands free module normally.

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. Check the wiring harness between hands free module connector C-11 (terminal 13) and fusible link (36).

- Check the power supply line for open circuit and short circuit.

NOTE: Also check ETACS-ECU connectors C-307 and C-317 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If ETACS-ECU connector C-307 or C-317 is damaged, repair or replace the damaged component(s).

Q: Is the wiring harness between hands-free module connector C-11 (terminal 13) and fusible link (36) in good condition?

YES : Replace the hands free module. The system should communicate with the hands free module normally.

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.