[13A] MULTIPORT FUEL INJECTION (MPI) <4G63> - - TROUBLESHOOTING - INSPECTION PROCEDURE FOR DIAGNOSIS CODES - Code No. P1603: Battery Backup Line System | PRINT PAGE / INDEX / PRIOR / NEXT

Code No. P1603: Battery Backup Line System
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
| STEP 1. Battery state checked Q: Is the battery terminal disconnected just before reading the diagnosis code? YES: Go to Step 2 . NO: Go to Step 3 .
| STEP 2 MUT-II/III diagnosis code Temporarily place the ignition switch in "LOCK (OFF)" position, and 10 seconds after that, place it in "ON" position again. Q: Is the diagnosis code P1603 set? YES: Go to Step 3 . NO: End of check.
| STEP 3. 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. 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.
| STEP 4. Connector check: C-111 engine-A/T-ECU connector
| Q: Is the check result normal? YES: Go to Step 5 . NO: Repair.
| STEP 5. Check the trouble symptoms. Q: Does trouble symptom persist? YES: Replace engine-A/T-ECU. NO: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ).

[13A] MULTIPORT FUEL INJECTION (MPI) <4G63> - - TROUBLESHOOTING - INSPECTION PROCEDURE FOR DIAGNOSIS CODES - Code No. P1603: Battery Backup Line System | PRINT PAGE / INDEX / PRIOR / NEXT

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