Hyundai Elantra: Engine Control System / Heated Oxygen Sensor (HO2S)
Description and operation
Heated Oxygen Sensor (HO2S) consists of the zirconium and the alumina and is installed on upstream and downstream of the Manifold Catalyst Converter (MCC).
In order that this sensor normally operates, the temperature of the sensor tip is higher than 370°C (698°F). So it has a heater which is controlled by the ECM duty signal.
When the exhaust gas temperature is lower than the specified value, the heater warms the sensor tip.

Specifications
[Bank 1 / Sensor 1]
Item
|
Specification
|
Heater Resistance (Ω)
| Approx. 2.5 [20°C (68°F)]
|
[Bank 1 / Sensor 2]
Item
|
Specification
|
Heater Resistance (Ω)
| Approx. 3.0 [20°C (68°F)]
|
Schematic diagrams

Harness Connector
HO2S [Bank 1 / Sensor 1]

HO2S [Bank 1 / Sensor 2]

Repair procedures
1. | Turn the ignition switch OFF. |
2. | Disconnect the HO2S connector. |
3. | Measure resistance between HO2S heater terminals 2 and 5. [B1 / S1] Measure resistance between HO2S heater terminals 3 and 4. [B1 / S2] |
4. | Check that the resistance is within the specification. [Bank 1 / Sensor 1]
Item
| Specification
| Heater Resistance (Ω)
| Approx. 2.5 [20°C (68°F)]
|
[Bank 1 / Sensor 2]
Item
| Specification
| Heater Resistance (Ω)
| Approx. 3.0 [20°C (68°F)]
|
|
1. | Turn ignition switch OFF and disconnect the battery negative (-) terminal. |
2. | Disconnect the heated oxygen sensor connector (A). |
3. | Remove the heated oxygen sensor (B). Tightening Torque : 39.2 - 49.0 N.m (4.0 - 5.0 kgf.m, 28.9 - 36.1 lb-ft) |
•
| Note that the SST (Part No. : 09392-2H100 or 09392-1Y100) is useful when removing the heated oxygen sensor. |
|

HO2S [Bank 1 / Sensor 1] 
HO2S [Bank 1 / Sensor 2] 

|
•
| Install the component with the specified torques. |
•
| Note that internal damage may occur when the component is dropped. In this case, use it after inspecting. |
|
•
| DON’T use a cleaner, spray, or grease to sensing element and connector of the sensor because oil component in them may malfunction the sensor performance. |
•
| Sensor and its wiring may be damaged in case of contacting with the exhaust system (Exhaust Manifold, Catalytic Converter, and so on). |
|
1. | Install in the reverse order of removal. |
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1. Turn the vehicle off.
2. Turn all other switches OFF.
3. Open the fuse panel cover.
4. Refer to the label on the inside of
the fuse panel cover to locate the
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5. Pull the suspected fuse straight out.
Use the removal tool provided in the
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