Inspection Procedure 4

INSPECTION PROCEDURE 4: The Audio Does Not Operate Normally By Operating The Radio And CD Player Of The Center Panel Unit.

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

Center Panel Unit Power Supply Circuit:

COMMENTS ON TROUBLE SYMPTOM
When the audio does not operate normally by operating the audio control unit of the center panel unit, the radio and CD player, center panel unit, or the power supply circuit system of center panel unit may be faulty.

PROBABLE CAUSES
- The radio and CD player may be defective.
- The center panel unit may be defective.
- Damaged harness wires and connectors

DIAGNOSIS

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

STEP 1. Check center panel unit connector C-124 and radio and CD player connector C-109 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are center panel unit connector C-124 and radio and CD player connector C-109 in good condition?

YES : Go to Step 2.

NO : Repair or replace the damaged component(s).

STEP 2. Check the wiring harness between center panel unit connector C-124 (terminal 1, 2) and radio and CD player connector C-109 (terminal 8, 18).

- Check the communication lines for open circuit and short circuit.

Q: Is the wiring harness between center panel unit connector C-124 (terminal 1, 2) and radio and CD player connector C-109 (terminal 8, 18) in good condition?

YES : Go to Step 3.

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 3. Check the ground circuit to the center panel unit. Measure the resistance at center panel unit connector C-124.







1. Disconnect the connector, and measure at the wiring harness side.
2. Measure resistance between terminal 9 and ground.

OK: The resistance should be 2 ohm or less.

Q: Is the measured resistance 2 ohms or less?

YES : Go to Step 5.

NO : Go to Step 4.

STEP 4. Check the wiring harness between center panel unit connector C-124 (terminal 9) and ground.

- Check the ground wires for open circuit.

Q: Is the wiring harness between center panel unit connector C-124 (terminal 9) and ground in good condition?

YES : Check the trouble symptom.

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 5. Check the power supply circuit to the center panel unit. Measure the voltage at center panel unit connector C-124.







1. Disconnect the connector, and measure at the harness side connector.
2. Measure voltage between terminal 7 and ground.
OK: Battery positive voltage

Q: Is the measured voltage battery voltage?

YES : Go to Step 7.

NO : Go to Step 6.

STEP 6. Check the wiring harness between center panel unit connector C-124 (terminal 7) and fusible link 36.

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

NOTE: Also ETACS-ECU connector C-307, C-317 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector ETACS-ECU connector C-307, C-317 are damaged, repair or replace the connector.

Q: Is the wiring harness between center panel unit connector C-124 (terminal 7) and fusible link 36 in good condition?

YES : Check the trouble symptom.

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 7. Replace the center panel unit temporarily, and check the trouble symptom.

Replace the center panel unit temporarily, and check that the audio works normally.

Q: Is the check result normal?

YES : Replace the center panel unit.

NO : Replace the radio and CD player.