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 connector terminal DCCT.
If the increasing voltage control system is abnormal, the DC/DC converter 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

Ignition switch is "ON" position.
The IOD fuse is installed.

Judgement Criterion

For 5 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 circuit or loose connector contact
Failed DC/DC converter
Failed AS&G-ECU

DIAGNOSIS PROCEDURE

STEP 1. Perform voltage measurement at C-65 DC/DC converter connector.

note

Before checking the voltage, carry out the operation, Step 1-3, to reset the diagnosis information of the DC/DC converter. 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 2.

	Replace the battery.

STEP 2. M.U.T.-III data list

Item 9: DC/DC converter 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 3.

	NO <Failure> : Perform the troubleshooting of diagnosis code No.B1301: DC/DC converter performance malfunction (Refer to ).

STEP 3. Perform voltage measurement at DC/DC converter 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 6.

	Go to Step 4.

STEP 4. Perform voltage measurement at AS&G-ECU connector by back probing.

Do not disconnect connector.
Ignition switch: ON
Voltage between terminal DCCA and earth.

OK: System voltage

Q. Is the check result normal?

	Repair the connector(s), or check of open circuit in DCCA line between AS&G-ECU connector and DC/DC converter connector.

	Go to Step 5.

STEP 5. 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 6. Check of harness damage in DCCA line between AS&G-ECU connector and DC/DC converter connector

Q. Is the check result normal?

	Go to Step 7.

	Repair the connector(s) or wiring harness.

STEP 7. Perform voltage measurement at DC/DC converter connector by back probing.

Do not disconnect connector.
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.