Inspection Procedure 18: Battery Run Down


COMMENT ON TROUBLE SYMPTOM



PROBABLE CAUSE



DIAGNOSIS PROCEDURE

STEP 1. Check battery voltage.

  • Measure battery voltage at cranking.
OK: 8 V or more

Q. Is the check result normal?
Go to Step 2 .
Check battery (Refer to GROUP 54A - Battery - On-vehicle Service - Battery Test ).

STEP 2. Connector check: B-119 alternator connector

Q. Is the check result normal?

Go to Step 3 .

Repair or replace.

STEP 3. Perform voltage measurement at B-119 alternator connector.


  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Voltage between terminal No. 3 and earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 5 .

Go to Step 4 .

STEP 4. Connector check: C-307 ignition switch connector


Q. Is the check result normal?


    Check intermediate connectors A-19, B-17, C-02, C-202, and repair if necessary. If intermediate connectors are normal, check and repair harness between B-119 (terminal No. 3) alternator connector and C-307 (terminal No. 2) ignition switch connector.

    • Check power supply line for open/short circuit.

Repair or replace.

STEP 5. Connector check: C-111 engine-A/T-ECU connector

Q. Is the check result normal?

Go to Step 6 .

Repair or replace.

STEP 6. Perform voltage measurement at C-111 engine-A/T-ECU connector.


  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Voltage between terminal No. 45 and earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 8 .

Go to Step 7 .

STEP 7. Check harness between C-111 (terminal No. 45) engine-A/T-ECU connector and B-119 (terminal No. 1) alternator connector.



  • Check output line for open/short circuit.

Q. Is the check result normal?

replace alternator.

Repair.

STEP 8. Perform voltage measurement at C-111 engine-A/T-ECU connector.


  • Measure engine-A/T-ECU terminal voltage.
  • Engine: Idling after warm-up
  • Transmission: P range
  • Radiator fan: Inactive
  • Voltage between terminal No. 45 and earth.
OK: Switching the headlamps to ON from OFF causes the voltage to increase.

Q. Is the check result normal?

Go to Step 9 .


    Replace alternator.

STEP 9. Check the trouble symptom.

Q. Does the trouble symptom persist?
Replace engine-A/T-ECU.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ).