Inspection Procedure 2: No sound is heard. <Vehicles with audio amplifier>


caution Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.












COMMENTS ON TROUBLE SYMPTOM



PROBABLE CAUSES



  • Malfunctions of audio unit
  • Malfunction of audio amplifier
  • Option coding information inconsistency
  • Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. 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 "Speaker" is set to "Premium."

Q. Is the check result normal?
Go to Step 2.
Operate the M.U.T.-III to set the option coding "Speaker" to "Premium," and check the trouble symptom.

STEP 2. Connector check: D-125 audio amplifier connector

Q. Is the check result normal?
Go to Step 3.
Repair the defective connector.

STEP 3. Resistance measurement at D-125 audio amplifier connector
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Measure the resistance between D-125 audio amplifier connector terminal No.24 and the body earth.
OK: Continuity exists (2 Ω or less)
(3)Measure the resistance between D-125 audio amplifier connector terminal No.31 and the body earth.
OK: Continuity exists (2 Ω or less)
(4)Measure the resistance between D-125 audio amplifier connector terminal No.32 and the body earth.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?
Go to Step 5.
Go to Step 4.

STEP 4. Check the wiring harness between D-125 audio amplifier connector terminal No.24, 31, 32 and the body earth

  • Check the earth wires for open circuit.

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Repair the wiring harness.

STEP 5. Voltage measurement at D-125 audio amplifier connector
(1)Disconnect the connector, and measure at the wiring harness-side connector.
(2)Voltage between D-125 audio amplifier connector terminal No.25 and the body earth
OK: System voltage
(3)Voltage between D-125 audio amplifier connector terminal No.35 and the body earth
OK: System voltage
(4)Voltage between D-125 audio amplifier connector terminal No.36 and the body earth
OK: System voltage

Q. Is the check result normal?
Go to Step 7.
Go to Step 6.

STEP 6. Check the wiring harness between D-125 audio amplifier connector terminal No.25, 35, 36 and the fusible link No.36

  • Check the power supply line for open circuit and short circuit.
note Prior to the wiring harness inspection, check intermediate connector C-131, and repair if necessary.

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Repair the wiring harness.

STEP 7. Connector check: C-16 audio unit connector

Q. Is the check result normal?
Go to Step 8.
Repair the defective connector.

STEP 8. Check the wiring harness between C-16 audio unit connector terminal No.7 and D-125 audio amplifier connector No.34

  • Check the communication lines for open circuit.

Q. Is the check result normal?

    Go to Step 9.
Repair the wiring harness.

STEP 9. Connector check: D-126 audio amplifier connector

Q. Is the check result normal?
Go to Step 10.
Repair the defective connector.

STEP 10. Check the wiring harness between C-16 audio unit connector terminal No.17 and D-126 audio amplifier connector No.3

  • Check the communication lines for open circuit.

Q. Is the check result normal?

    Go to Step 11.
Repair the wiring harness.

STEP 11. Retest the system
Replace the audio amplifier, then check that the audio sound is output.

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Replace the audio unit.