OPERATION
- Power is directly supplied to the engine-A/T-ECU (terminal No. 66) from the battery.
FUNCTION
- Direct power supply from the battery enables the engine-A/T-ECU to store the backup RAM information even when the ignition switch is in "OFF" position.
TROUBLE JUDGMENT
Check Condition
- Ignition switch: ON
Judgment Criterion
- The previous back up RAM information when the ignition switch was in "OFF" position is not stored.
PROBABLE CAUSE
- Open/short circuit in battery backup line circuit or loose connector contact
- Failed engine-A/T-ECU
DIAGNOSIS PROCEDURE
)
- Disconnect connector, and measure at harness side.
- Ignition switch: ON
- Voltage between terminal No. 66 and earth.
OK: System voltage
Q: Is the check result normal?
YES:
Go to Step 4 
.NO:
- Check intermediate connectors A-14, C-106, C-125, C-202 and C-204, and repair if necessary. If intermediate connectors are normal, check and repair harness between battery and C-111 (terminal No. 66) engine-A/T-ECU connector.
- Check power supply line for open/short circuit.
Q: Is the check result normal?
YES:
Go to Step 5 .NO: Repair.
