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TROUBLESHOOTING MULTIPORT FUEL INJECTION (MFI) 13A-79 TROUBLE JUDGMENT Judgment Criteria The engine coolant temperature is approximately. C or higher. The oxygen sensor heater (rear) is in "ON" posi- The engine speed is 50 r/min or more. The battery voltage is 11 - 16 V. Judgment Criteria The heater current of front oxygen sensor heater PROBABLE CAUSE Failed oxygen sensor heater (rear) Open/short circuit in oxygen sensor (rear) circuit Failed engine-ECU DIAGNOSIS PROCEDURE STEP 1. Connector check: C-18 oxygen sensor Q: Is the check result normal? YES : Go to Step 2 . NO : Repair. STEP 2. Measure resistance at C-18 oxygen Disconnect connector, and measure at sensor Resistance between terminal No. 1 and No. 2. OK: 11 - 18 W Q: Is the check result normal? YES : Go to Step 3 . NO : Replace oxygen (rear) sensor. STEP 3. Measure voltage at C-18 oxygen sensor Disconnect connector, and measure at harness Ignition switch: ON Voltage between terminal No. 2 and earth. OK: System voltage Q: Is the check result normal? YES : Go to Step 5 . NO : Go to Step 4 . AK300270 1 2 3 4 AB Connector: C-18 Oxygen sensor (rear) C-18 Harness side AK300270 1 2 3 4 AB Connector: C-18 Oxygen sensor (rear) C-18 Harness side AK300270 1 2 3 4 AB Connector: C-18 Oxygen sensor (rear) C-18 Harness side |