HEATED OXYGEN SENSOR (HO2S) (EXCEPT AUSTRALIAN SPECS.), FRONT HEATED OXYGEN SENSOR (HO2S) (AUSTRALIAN SPECS.) INSPECTION [AJ (3.0L Duratec)]

Note

• Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart. (See Troubleshooting Procedure.)

HO2S Voltage Inspection

1. Start the engine and warm it up.

2. Disconnect the HO2S connector.

3. Connect the positive probe of the tester (digital type) to HO2S terminal 4, the negative probe to HO2S terminal 3, and then measure the voltage.

4. Run the engine at 3,000 rpm until the voltage indicates approx. 0.5-0.7 V.

5. Verify that the voltage is as indicated in the table when the engine is raced repeatedly.

• If the voltage is not as indicated in the table, replace the HO2S. (See HEATED OXYGEN SENSOR (HO2S) (EXCEPT AUSTRALIAN SPECS.), FRONT HEATED OXYGEN SENSOR (HO2S) (AUSTRALIAN SPECS.) REMOVAL/INSTALLATION [AJ (3.0L Duratec)].)

• If the monitor item status/specification (reference) is not within the specification, even though the resistance is within the specification, perform the "Circuit Open/Short Inspection".

HO2S output voltage

HO2S Heater Resistance Inspection

1. Disconnect the HO2S connector.

2. Measure the resistance between HO2S terminals 1 and 2.

• If it is not within the specification, replace the HO2S. (See HEATED OXYGEN SENSOR (HO2S) (EXCEPT AUSTRALIAN SPECS.), FRONT HEATED OXYGEN SENSOR (HO2S) (AUSTRALIAN SPECS.) REMOVAL/INSTALLATION [AJ (3.0L Duratec)].)

• If the monitor item status/specification (reference) is not within the specification, even though the resistance is within the specification, perform the "Circuit Open/Short Inspection".

HO2S heater resistance

3-30 ohms