NGK OZA639-EAF1-91638 Oxygen Sensor 91638 Total Length 535mm

【NGK OZA639-EAF1-91638 Oxygen Sensor 91638 Total Length 535mm O2】
■Product Description
NTK O2 Sensor Detects Ideal Air-Fuel Ratio
Advanced control is required to reduce harmful substances (HC, CO, NOx) in exhaust gas, and O2 sensors play an important role in detecting the oxygen concentration in the exhaust gas and providing feedback to the ECU*1.
NTK O2 sensors detect the oxygen concentration in the exhaust gas and provide feedback to the ECU so that the fuel-air mixture ratio (air-fuel ratio) is the optimal stoichiometric air-fuel ratio "λ (lambda) = 1*2". The ECU uses the signal from the O2 sensor to control the fuel mixture; if the fuel is too rich compared to the stoichiometric air-fuel ratio, it thins the fuel, and if it's too lean, it enriches the fuel, thereby maintaining control near the stoichiometric air-fuel ratio, which most effectively purifies harmful substances in the exhaust gas. Thus, NTK O2 sensors are crucial components in reducing harmful substances in exhaust gas.

Specifications
【Features and Structure】
Zirconia elements have the characteristic of generating electromotive force due to differences in oxygen concentration at temperatures exceeding 300°C. Utilizing this characteristic, zirconia type sensors detect the difference in oxygen concentration between the inside and outside of the element (atmosphere and exhaust gas) and provide feedback to the ECU whether the fuel is rich or lean relative to the stoichiometric air-fuel ratio.
Wide-range air-fuel ratio sensors can detect how rich or lean the fuel is relative to the stoichiometric air-fuel ratio. Therefore, more precise engine control is possible compared to zirconia O2 sensors. Additionally, engine control other than the stoichiometric air-fuel ratio (λ=1), such as lean burn control, becomes possible. There are also early activation wide-range air-fuel ratio sensors that maintain the characteristics of conventional wide-range air-fuel ratio sensors while improving heat resistance and durability, and achieve early activation (starts operating within 5 seconds after the engine key is turned ON) through an integrated structure of the element and heater.
【Necessity of Replacement】
O2 sensors are constantly exposed to exhaust gas exceeding 600°C and accumulate combustion products, working in a very harsh environment.
Using a deteriorated or damaged O2 sensor can lead to various problems.
After 5 years or 80,000 km from a new car*
*May vary depending on vehicle usage conditions.
Total length: 535mm
Total length is the length from the gasket to the tip of the connector.
Compatible Manufacturer: Subaru
Compatible Genuine Part Number: 22690KA371

■Image Notes
*Images are for illustration purposes only. Includes products with different sizes and colors. Product designs and specifications may change without prior notice. Please understand.

■Precautions
O2 sensors have dedicated types set for each vehicle model and engine, so there is no interchangeability with other types.
(1) Always stop the engine before inspecting, replacing, or adjusting.
(2) Inspect and replace according to the service manual of each automobile manufacturer.
(3) Use the correct part number O2 sensor as specified in this document.
(4) It may not function correctly if used in modified vehicles, etc.
(5) Be careful as dropping or impacting the sensor may crack the internal ceramic element.
(6) Anti-seize compound is applied to the threaded part of the sensor. To prevent dust and debris from adhering,
remove the protective cap immediately before installing the sensor.
(7) Do not wipe off the anti-seize compound.
(8) If anti-seize compound adheres to your hands or other parts, wash it off immediately with water.
➈ Do not twist or bend the lead wire fixed to the main body.
➉ Do not use an impact wrench when installing the sensor.
(11) To install the sensor, thread it in with your fingertips, then use a wrench to tighten it to the following approximate torque:
【Part numbers starting with "LZA", "OZA", "OZR", "UAR"】:
Sensors with thread diameter 18mm, pitch 1.5mm, Hex 22mm = approx. 45-55 N・m (4.5-5.5 kgf・m)
(12) Do not allow the lead wire or connector to touch the exhaust manifold or other hot parts.
(13) Route the lead wire in the same way as the original and securely attach the connector.
(14) Depending on the condition of your vehicle, replacing the O2 sensor alone may not resolve the problem.
(15) When the MIL is illuminated, before (or after) replacing the sensor, follow the service manual, etc.,
and be sure to clear (reset) the diagnostic (self-diagnosis/OBD) error code.
Failure to clear the error code may lead to problems such as the MIL not turning off.