Code No. B1302: DC/DC converter (Entertainment System) System




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 high signal (OFF signal) is received in a row.

FAIL-SAFE AND BACKUP FUNCTION



  • None.

PROBABLE CAUSES



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


note Before checking the voltage, 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.

  • Disconnect connector, and measure at harness side.
  • Voltage between terminal PWR and earth.
OK: Not more than 20 V

Q. Is the check result normal?

Go to Step 3.
Replace the battery.

STEP 3. M.U.T.-III data list



  • 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 ).
NO <OFF> : Go to Step 4.
NO <Failure> : Perform the troubleshooting of diagnosis code No. B1301: DC/DC converter (entertainment system) performance malfunction (Refer to ).

STEP 4. 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 7.
Go to Step 5.

STEP 5. Perform voltage measurement at AS&G-ECU connector by back probing.



  • Measure the voltage AS&G-ECU connector terminal.
  • Ignition switch: ON
  • Voltage between terminal DCCA and earth.
OK: System voltage

Q. Is the check result normal?

Repair the connector(s), or check and repair of open circuit in DCCA line between AS&G-ECU connector and DC/DC converter (entertainment system) connector.
Go to Step 6.

STEP 6. 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 7. Check of harness damage in DCCA line between AS&G-ECU connector and DC/DC converter (entertainment system) connector


Q. Is the check result normal?

Go to Step 8.
Repair the connector(s) or wiring harness.

STEP 8. Perform voltage measurement at C-65 DC/DC converter (entertainment system) connector by back probing.



  • Measure the voltage C-65 DC/DC converter (entertainment system) connector terminal.
  • Ignition switch: ON
  • Voltage between terminal DCCA and earth.
OK: 1 V or less

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 ).
Replace the DC/DC converter (entertainment system).