Code No. B1301: DC/DC Converter (Entertainment System) Performance


OPERATION



  • At the auto start, the AS&G-ECU connector terminal DCCT sends increasing voltage request signal to the DC/DC converter (entertainment system) connector terminal DCCT.
  • If the increasing voltage control system is abnormal, the DC/DC converter (entertainment system) connector terminal DCCA should send the diagnostic signal to the AS&G-ECU connector terminal DCCA.

FUNCTION



  • The AS&G-ECU checks whether the increasing voltage control system is normal.

TROUBLE JUDGMENT


Check Condition
  • For 2 seconds after the ignition switch is "ON" position.
  • Battery voltage is 6.3 V or more.
  • The IOD fuse is installed.
Judgement Criterion
  • For 2 seconds, the duty signal (failure signal) is received in a row.

FAIL-SAFE AND BACKUP FUNCTION



  • None.

PROBABLE CAUSES



  • Connection with accessories having rated output current large enough to possibly cause overloads (overcurrents).
  • Modified circuit
  • Failed battery
  • Open/short circuit or harness damage in DC/DC converter (entertainment system) circuit or loose connector contact
  • Failed DC/DC converter (entertainment system)
  • Failed AS&G-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code

Q. Is diagnosis code No. B1354 set?
Perform the troubleshooting of diagnosis code No. B1354: DC/DC converter (entertainment system) control circuit .
Go to Step 2.

STEP 2. Check the vehicle status for use

  • Ask the user whether he or she connects the vehicle with accessories having the rated output current large enough to possibly cause overloads (overcurrents) or not. Or ask the user whether he or she modifies the circuit or not.

Q. Does the user connect the vehicle with accessories having the large rated output current? Or does the user modify the circuit?
Turn OFF the accessories or remove them. Then go to Step 3.
Go to Step 3.

STEP 3. M.U.T.-III data list
note Before checking the data list, carry out the operation, Step 1-3, to reset the diagnosis information of the DC/DC converter (entertainment system). If the operation is swiftly carried out, the diagnosis code can be stored. Slowly carry out the operation, Step 1-3.

  1. Turn the ignition switch to "ACC" position.
  2. Turn the ignition switch to "LOCK" (OFF) position.
  3. Repeat Steps 1-2.
  4. Turn the ignition switch to "ON" position and check the data list after having passed for more than 60 seconds.

  • Item 9: DC/DC converter (entertainment system) diagnostic signal

    OK: ON

Q. Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
Go to Step 4.

STEP 4. Check the operation of the accessories

  • Ignition switch: ACC
OK: Radio and CD player operates

Q. Is the check result normal?
Go to Step 5.
Perform the troubleshooting of the radio and CD player (Refer to GROUP 54A - Radio and CD Player - Symptom Chart ).

STEP 5. Check the DC/DC converter (entertainment system) power supply circuit

  • Check the DC/DC converter (entertainment system) power supply circuit (Refer to GROUP 54A - DC/DC Converter - Symptom Procedures - Check the DC/DC Converter Power Supply Circuit ).

Q. Is the check result normal?
Go to Step 6.
Repair the circuit according to the troubleshooting and go to Step 6.

STEP 6. Perform voltage measurement at AS&G-ECU connector.

  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Voltage between terminal DCCT and earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 8.
Go to Step 7.

STEP 7. Check of short to earth and open circuit in DCCT line between DC/DC converter (entertainment system) connector and AS&G-ECU connector


Q. Is the check result normal?
Replace the DC/DC converter (entertainment system).
Repair the connector(s) or wiring harness.

STEP 8. Perform voltage measurement at AS&G-ECU connector by back probing.

  • Do not disconnect connector.
  • Ignition switch: ON
  • Voltage between terminal DCCT and earth.
OK: 1 V or less

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

STEP 9. M.U.T.-III diagnosis code

  • Reconfirmation of the diagnosis code.

Q. Is the diagnosis code set?
Replace the AS&G-ECU.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

STEP 10. Perform voltage measurement at DC/DC converter (entertainment system) connector.

  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Voltage between terminal DCCA and earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 11.

    Repair the connector(s), or check and repair of short to earth in DCCA line between DC/DC converter (entertainment system) connector and AS&G-ECU connector.

STEP 11. Check of harness damage in DCCT line between AS&G-ECU connector and DC/DC converter (entertainment system) connector


Q. Is the check result normal?
Go to Step 12.
Repair the connector(s) or wiring harness.

STEP 12. Perform voltage measurement at DC/DC converter (entertainment system) connector by back probing.



  • Measure the voltage C-65 DC/DC converter (entertainment system) connector terminal.
  • Measure the voltage between terminal OUT1 and earth at auto start.
  • Measure the voltage between terminal OUT2 and earth at auto start.
  • Check the difference among the measured voltage of the terminal OUT1 and the measured voltage of the terminal OUT2.
OK: Under 0.3 V

Q. Is the check result normal?
Go to Step 13.
Replace the DC/DC converter (entertainment system).

STEP 13. M.U.T.-III diagnosis code
note Before rechecking the diagnosis code is set, carry out the operation, Step 1-3, to reset the diagnosis information of the DC/DC converter (entertainment system). If the operation is swiftly carried out, the diagnosis code can be stored. Slowly carry out the operation, Step 1-3.

  1. Turn the ignition switch to "ACC" position.
  2. Turn the ignition switch to "LOCK" (OFF) position.
  3. Repeat Steps 1-2.
  4. Confirm again whether the diagnosis code is set.

Q. Is the diagnosis code set?
Replace the DC/DC converter (entertainment system). Then go to Step 14 .
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

STEP 14. M.U.T.-III diagnosis code

  • Reconfirmation of the diagnosis code.

Q. Is the diagnosis code set?
Replace the AS&G-ECU.
Check end.