No Sound is Heard From one of the Speakers. [Vehicles With Audio Amplifier]

Inspection Procedure 3: No sound is heard from one of the speakers.

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

Speaker System Circuit Part 1:

Speaker System Circuit Part 2:

Speaker System Circuit Part 3:

COMMENTS ON TROUBLE SYMPTOM
If the sound is not heard from one of the speakers, the speaker, audio visual navigation unit, audio amplifier, communication line from the audio visual navigation unit to the audio amplifier, or communication line from the audio amplifier to the speaker may have a problem. Also, the option coding information may be inconsistent.

PROBABLE CAUSES
- Malfunction of speaker
- Malfunctions of audio visual navigation unit
- Malfunction of audio amplifier
- Option coding information inconsistency
- Damaged harness wires and connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A

STEP 1. ETACS-ECU coding data check.

1. Operate scan tool MB991958 to read the ETACS-ECU option coding information. (Refer to Coding Table)
2. Check that the "Speaker" is set to "Premium."

Q: Is the check result normal?

YES: Go to Step 2.

NO: Operate scan tool MB991958 to set the option coding "Speaker" to "Premium," and check the trouble symptom.

STEP 2. Checking with audio speaker check.

Perform the audio speaker check, and check which speaker does not output the sound.

Q: Is the check result normal?

YES: The trouble can be an intermittent malfunction (Refer to How to Cope with Intermittent Malfunction).

NO: Refer to Inspection Procedure 2 "No sound is heard".

NO: Go to Step 3.

NO: Go to Step 9.

NO: Go to Step 15.

NO: Go to Step 19.

NO: Go to Step 23.

NO: Go to Step 27.

NO: Go to Step 31.

STEP 3. Check front door speaker (RH) connector E-04 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is front door speaker (RH) connector E-04 in good condition?

YES: Go to Step 4.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection.

STEP 4. Check the front door speaker (RH).

1. Remove the front door speaker (RH).




2. Check that the front door speaker (RH) outputs the noise when five volts are applied to the front door speaker (RH) connector terminal.

Q: Does the front door speaker (RH) output the noise?

YES: Go to Step 5.

NO: Replace the front door speaker (RH).

STEP 5. Check audio amplifier connector D-126 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is audio amplifier connector D-126 in good condition?

YES: Go to Step 6.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection.

STEP 6. Check the wiring harness between audio amplifier connector D-126 (terminal 27, 37) and front door speaker (RH) connector E-04 (terminal 1, 2).

NOTE: Also check intermediate connectors C-20 and C-112 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-20 or C-112 is damaged, repair or replace the connector as described in, Harness Connector Inspection.

Check the communication lines for open circuit.

Q: Is the wiring harness between audio amplifier connector D-126 (terminal 27, 37) and front door speaker (RH) connector E-04 (terminal 1, 2) in good condition?

YES: Go to Step 7.

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. Check audio visual navigation unit connector C-10 and audio amplifier connector D-127 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are audio visual navigation unit connector C-10 and audio amplifier connector D-127 in good condition?

YES: Go to Step 8.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection.

STEP 8. Check the wiring harness between audio visual navigation unit connector C-10 (terminal 7, 15) and audio amplifier connector D-127 (terminal 11, 10).

NOTE: Also check intermediate connectors C-17 and C-22 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-17 or C-22 is damaged, repair or replace the connector as described in, Harness Connector Inspection.

Check the communication lines for open circuit.

Q: Is the wiring harness between audio visual navigation unit connector C-10 (terminal 7, 15) and audio amplifier connector D-127 (terminal 11, 10) in good condition?

YES: Check the trouble symptom, and go to Step 35.

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 9. Check front door speaker (LH) connector E-17 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is front door speaker (LH) connector E-17 in good condition?

YES: Go to Step 10.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection.

STEP 10. Check the front door speaker (LH).

1. Remove the front door speaker (LH).




2. Check that the front door speaker (LH) outputs the noise when five volts are applied to the front door speaker (LH) connector terminal.

Q: Does the front door speaker (LH) output the noise?

YES: Go to Step 11.

NO: Replace the front door speaker (LH).

STEP 11. Check audio amplifier connector D-126 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is audio amplifier connector D-126 in good condition?

YES: Go to Step 12.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection.

STEP 12. Check the wiring harness between audio amplifier connector D-126 (terminal 28, 38) and front door speaker (LH) connector E-17 (terminal 1, 2).

NOTE: Also check intermediate connectors C-20 and C-126 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-20 or C-126 is damaged, repair or replace the connector as described in, Harness Connector Inspection.

Check the communication lines for open circuit.

Q: Is the wiring harness between audio amplifier connector D-126 (terminal 28, 38) and front door speaker (LH) connector E-17 (terminal 1, 2) in good condition?

YES: Go to Step 13.

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 13. Check audio visual navigation unit connector C-10 and audio amplifier connector D-127 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are audio visual navigation unit connector C-10 and audio amplifier connector D-127 in good condition?

YES: Go to Step 14.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection.

STEP 14. Check the wiring harness between audio visual navigation unit connector C-10 (terminal 3, 12) and audio amplifier connector D-127 (terminal 12, 4)

Check the communication lines for open circuit.

NOTE: Also check intermediate connectors C-17 and C-22 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-17 or C-22 is damaged, repair or replace the connector as described in, Harness Connector Inspection.

Q: Is the wiring harness between audio visual navigation unit connector C-10 (terminal 3, 12) and audio amplifier connector D-127 (terminal 12, 4) in good condition?

YES: Check the trouble symptom, and go to Step 35.

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 15. Check rear door speaker (RH) connector E-24 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is rear door speaker (RH) connector E-24 in good condition?

YES: Go to Step 16.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection.

STEP 16. Check the rear door speaker (RH).

1. Remove the rear door speaker (RH).




2. Check that the rear door speaker (RH) outputs the noise when five volts are applied to the rear door speaker (RH) connector terminal.

Q: Does the rear door speaker (RH) output the noise?

YES: Go to Step 17.

NO: Replace the rear door speaker (RH).

STEP 17. Check audio amplifier connector D-127 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is audio amplifier connector D-127 in good condition?

YES: Go to Step 18.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection.

STEP 18. Check the wiring harness between audio amplifier connector D-127 (terminal 2, 8) and rear door speaker (RH) connector E-24 (terminal 1, 2).

NOTE: Also check intermediate connector D-36 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector D-36 is damaged, repair or replace the connector as described in, Harness Connector Inspection.

Check the communication lines for open circuit.

Q: Is the wiring harness between audio amplifier connector D-127 (terminal 2, 8) and rear door speaker (RH) connector E-24 (terminal 1, 2) in good condition?

YES: Check the trouble symptom, and go to Step 35.

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 19. Check rear door speaker (LH) connector E-10 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is rear door speaker (LH) connector E-10 in good condition?

YES: Go to Step 20.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection.

STEP 20. Check the rear door speaker (LH).

1. Remove the rear door speaker (LH).




2. Check that the rear door speaker (LH) outputs the noise when five volts are applied to the rear door speaker (LH) connector terminal.

Q: Does the rear door speaker (LH) output the noise?

YES: Go to Step 21.

NO: Replace the rear door speaker (LH).

STEP 21. Check audio amplifier connector D-127 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is audio amplifier connector D-127 in good condition?

YES: Go to Step 22.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection.

STEP 22. Check the wiring harness between audio amplifier connector D-127 (terminal 1, 7) and rear door speaker (LH) connector E-10 (terminal 1, 2).

NOTE: Also check intermediate connector D-21 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector D-21 is damaged, repair or replace the connector as described in, Harness Connector Inspection.

Check the communication lines for open circuit.

Q: Is the wiring harness between audio amplifier connector D-127 (terminal 1, 7) and rear door speaker (LH) connector E-10 (terminal 1, 2) in good condition?

YES: Check the trouble symptom, and go to Step 35.

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 23. Check tweeter (RH) connector E-02 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is tweeter (RH) connector E-02 in good condition?

YES: Go to Step 24.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection.

STEP 24. Check the tweeter (RH).

1. Remove the tweeter (RH).




2. Check that the tweeter (RH) outputs the noise when five volts are applied to the tweeter (RH) connector terminal.

Q: Does the tweeter (RH) output the noise?

YES: Go to Step 25.

NO: Replace the tweeter (RH).

STEP 25. Check audio amplifier connector D-127 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is audio amplifier connector D-127 in good condition?

YES: Go to Step 26.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection.

STEP 26. Check the wiring harness between audio amplifier connector D-127 (terminal 5, 13) and tweeter (RH) connector E-02 (terminal 2, 1).

NOTE: Also check intermediate connectors C-22 and C-113 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-22 or C-113 is damaged, repair or replace the connector as described in, Harness Connector Inspection.

Check the communication lines for open circuit.

Q: Is the wiring harness between audio amplifier connector D-127 (terminal 5, 13) and tweeter (RH) connector E-02 (terminal 2, 1) in good condition?

YES: Check the trouble symptom, and go to Step 35.

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 27. Check tweeter (LH) connector E-14 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is tweeter (LH) connector E-14 in good condition?

YES: Go to Step 28.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection.

STEP 28. Check the tweeter (LH).

1, Remove the tweeter (LH).




2. Check that the tweeter (LH) outputs the noise when five volts are applied to the tweeter (LH) connector terminal.

Q: Does the tweeter (LH) output the noise?

YES: Go to Step 29.

NO: Replace the tweeter (LH).

STEP 29. Check audio amplifier connector D-127 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is audio amplifier connector D-127 in good condition?

YES: Go to Step 30.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection.

STEP 30. Check the wiring harness between audio amplifier connector D-127 (terminal 6, 14) and tweeter (LH) connector E-14 (terminal 2, 1).

NOTE: Also check intermediate connectors C-22 and C-113 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-22 or C-113 is damaged, repair or replace the connector as described in, Harness Connector Inspection.

Check the communication lines for open circuit.

Q: Is the wiring harness between audio amplifier connector D-127 (terminal 6, 14) and tweeter (LH) connector E-14 (terminal 2, 1) in good condition?

YES: Check the trouble symptom, and go to Step 35.

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 31. Check subwoofer connector D-15 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is subwoofer connector D-15 in good condition?

YES: Go to Step 32.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection.

STEP 32. Check the Subwoofer.

1. Remove the subwoofer.




2. Check that the subwoofer outputs the noise when five volts are applied to the subwoofer connector terminal.

Q: Does the subwoofer output the noise?

YES: Go to Step 33.

NO: Replace the subwoofer.

STEP 33. Check audio amplifier connector D-126 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is audio amplifier connector D-126 in good condition?

YES: Go to Step 34.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection.

STEP 34. Check the wiring harness between audio amplifier connector D-126 (terminal 21, 22, 29, 30) and subwoofer connector D-15 (terminal 4, 2, 3, 1).

Check the communication lines for open circuit.

Q: Is the wiring harness between audio amplifier connector D-126 (terminal 21, 22, 29, 30) and subwoofer connector D-15 (terminal 4, 2, 3, 1) in good condition?

YES: Check the trouble symptom, and go to Step 35.

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 35. Replace the audio amplifier temporarily, and check the trouble symptom.

Replace the audio amplifier temporarily, and check that the sound is output from the speaker.

Q: Is the check result normal?

YES: The trouble can be an intermittent malfunction (Refer to How to use Troubleshooting/inspection Service Points, How to Cope with Intermittent Malfunction).

NO: Replace the audio visual navigation unit.