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
If the audio sound is not output, the audio unit, audio amplifier, or power supply circuit
of audio amplifier may have a problem, or the option coding information may be inconsistent.
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 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: Battery voltage
(3)Voltage between D-125 audio amplifier connector terminal No.35 and the body earth OK: Battery voltage
(4)Voltage between D-125 audio amplifier connector terminal No.36 and the body earth OK: Battery 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
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 ).
)
)
)
)
)
)
).
Go to Step 2.
Operate the M.U.T.-III to set the option coding "Speaker" to "Premium," and check
the trouble symptom.