Inspection Procedure 1: No navigation screen is displayed. <Vehicles with Auto Stop & Go (AS&G) System>


caution Before replacing the multivision display, ensure that the power supply circuit, the earth circuit, and the communication circuit are normal. (Check that the voltage is 10 V or more.)

COMMENTS ON TROUBLE SYMPTOM
When the ignition switch is turned to the ACC or ON position, if the screen is not displayed at all, the power supply circuit, DC/DC converter or multivision display may have a problem.

PROBABLE CAUSES

  • Malfunction of power supply circuit
  • Malfunction of DC/DC converter
  • Malfunction of multivision display

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III other system data list
Check the input signal of ACC relay.

  • Turn the ignition switch to the ACC position.
Item No.
 Item name
 Normal condition
Item 288
 ACC switch
 ON
OK: Normal condition is displayed.

Q. Is the check result normal?
Go to Step 2
Refer to ETACS - Input Signal Procedure 1 "The ignition switch (ACC) signal is not sent to the ETACS-ECU" .

STEP 2. Check the DC/DC converter.
Check the continuity of the DC/DC converter.

Q. Is the check result normal?
Go to Step 3
Replace the DC/DC converter.

STEP 3. Voltage measurement at DC/DC converter connector (IGN terminal).
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Turn the ignition switch to the ACC position.
(3)Check the voltage between DC/DC converter connector (IGN terminal) and body earth.
OK: System voltage

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

STEP 4. Check of short to power supply, short to earth, and open circuit in IGN line between DC/DC converter connector and ETACS-ECU connector

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 connector(s) or wiring harness.

STEP 5. Voltage measurement at DC/DC converter connector (PWR terminal).
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Check the voltage between DC/DC converter connector (PWR terminal) and body earth.
OK: System voltage

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

STEP 6. Check of short to power supply, short to earth, and open circuit in PWR line between fusible link and DC/DC converter connector

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 connector(s) or wiring harness.

STEP 7. Check the wiring harness between the DC/DC converter connector terminal and the multivision display connector terminal.

  • Check of short to power supply, short to earth, and open circuit in OUT1 line between DC/DC converter connector and multivision display connector.
  • Check of short to power supply, short to earth, and open circuit in OUT2 line between DC/DC converter connector and multivision display connector.

Q. Is the check result normal?
Go to Step 8
Repair the connector(s) or wiring harness.

STEP 8. Resistance measurement at multivision display connector (GND, GND2 terminal).
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Check the continuity between the multivision display connector (GND terminal) and body earth.
OK: Continuity exists (2 Ω or less)
(3)Check the continuity between the multivision display connector (GND2 terminal) and body earth.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?
Go to Step 10
Go to Step 9

STEP 9. Check of open circuit in GND or GND2 line between multivision display connector and body earth

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 connector(s) or wiring harness.

STEP 10. Retest the system
Check if the multivision display power is turned ON.

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 multivision display.