Inspection Procedure 2: Audio equipment is reset or sound jump occurs at auto start.


caution Even when the diagnosis code No. B1301 or B1302 is set in the AS&G-ECU, do not conclude as a DC/DC converter or AS&G-ECU error, and be sure to check the DC/DC converter power supply circuit.

COMMENTS ON TROUBLE SYMPTOM
If a reset or sound jump occurs with the AUDIO equipment at the auto start, the following causes can be suspected.

  • Diagnosis code No. B1301 or B1302 is stored in AS&G-ECU, and voltage is not boosted by DC/DC converter at auto start
  • DC/DC converter internal malfunction
  • Battery voltage drop
  • Communication error with AS&G-ECU and DC/DC converter
  • AS&G-ECU malfunction
note If a reset or sound jump occurs with AUDIO equipment at other than the auto start, a problem is present with the power supply to the equipment that experienced the reset or sound jump. Therefore, be sure to check the power supply to the equipment.

PROBABLE CAUSES

  • The DC/DC converter (Entertainment) may be defective.
  • The AS&G-ECU may be defective.
  • The battery may be defective.
  • Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. Check the power supply system circuit
Check the DC/DC converter power supply circuit by referring to Troubleshooting. (Refer to .)

Q. Is the check result normal?
Go to Step 2
Repair according to the troubleshooting, and recheck the trouble symptom.

STEP 2. Check the M.U.T.-III Diagnosis code for other systems
Check if the diagnosis code No. B1301 or B1302 is set to AS&G-ECU.

Q. Is the diagnosis code set?
Erase the diagnosis code, and then go to Step 3.
Go to Step 3

STEP 3. Check the M.U.T.-III Diagnosis code for other systems
Check if the diagnosis code is set to AS&G-ECU.

Q. Is the diagnosis code set?
Diagnose the AS&G-ECU (Refer to GROUP 17 - Troubleshooting ).
Go to Step 4

STEP 4. Battery test
Check the battery state.(Refer to .)

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

STEP 5. Check of short to power supply, short to earth, and open circuit in OUT1, OUT2 line between DC/DC converter (Entertainment) connector and intermediate connector

Q. Is the check result normal?
Go to Step 6.
Repair the connector(s) or wiring harness.

STEP 6. Replace the DC/DC converter (Entertainment) temporarily, and check the trouble symptom.

Q. Is the check result normal?
Replace the DC/DC converter (Entertainment) (Entertainment).
Replace the AS&G-ECU.