Diagnosis Item 34: Diagnose when the M.U.T.-III cannot receive the data sent by display audio. <Vehicles with display audio>



caution When servicing a CAN bus line, earth yourself by touching a metal object such as an unpainted water pipe. If you fail to do, a component connected to the CAN bus line may be broken.

FUNCTION


The diagnostic result demonstrates that "the M.U.T.-III cannot receive the sent data from the display audio" when the M.U.T.-III checks the periodically sent data from each ECU and cannot receive the display audio <Vehicles with display audio> data only.

TROUBLE JUDGEMENT CONDITIONS


M.U.T.-III judges the trouble when the periodically sent data from display audio <Vehicles with display audio> cannot be received.

PROBABLE CAUSES




DIAGNOSIS PROCEDURE


STEP 1. Connector check: joint connector (CAN5) and radio and CD player connector <Vehicles with display audio>


caution The strand end of the twist wire should be within 10 cm from the connector.
When checking the joint connector, ensure that its wiring harness side and its short pins are not damaged.

Q. Is the check result normal?

Go to Step 2.
Repair the defective connector. Replace the joint connector as necessary.

STEP 2. Resistance measurement at joint connector (CAN5) and radio and CD player connector <Vehicles with display audio>.


caution A digital multimeter should be used.
caution The test wiring harness should be used.
(1)Disconnect joint connector (CAN5) and the radio and CD player connector <Vehicles with display audio>, and measure at the wiring harness side.
(2)Turn the ignition switch to the LOCK (OFF) position.
(3)
caution When measuring the resistance, disconnect the negative battery terminal.
Ensure that the negative battery terminal is disconnected.
(4)Continuity between joint connector (CAN5) terminal No.7 and radio and CD player connector <Vehicles with display audio> terminal No.3
OK: Continuity (2 Ω or less)
(5)Continuity between joint connector (CAN5) terminal No.18 and radio and CD player connector <Vehicles with display audio> terminal No.13
OK: Continuity (2 Ω or less)
caution Strictly observe the specified wiring harness repair procedure.

Q. Is the check result normal?

<All the resistances measure 2 Ω or less> Go to Step 3.
NO : <Either or all of the resistances measure more than 2 Ω> Repair the wiring harness between joint connector (CAN5) and the radio and CD player connector <Vehicles with display audio>.

STEP 3. Resistance measurement at radio and CD player connector <Vehicles with display audio>.


caution A digital multimeter should be used.
(1)Remove the radio and CD player connector <Vehicles with display audio>, and measure at the equipment side.
(2)Resistance between radio and CD player connector <Vehicles with display audio> terminal Nos.3 and 13
OK: 1 kΩ or more

Q. Is the check result normal?

Power supply to the radio and CD player <Vehicles with display audio> may be suspected. Diagnose the display audio <Vehicles with display audio>. Refer to GROUP 54A - Troubleshooting <Vehicles with display audio>.
Replace the radio and CD player <Vehicles with display audio>.