NGK OZA721-EE25-94137 Oxygen Sensor 94137 Total length 850mm

【NGK OZA721-EE25-94137 Oxygen Sensor 94137 Total Length 850mm O2】
■Product Description
NTK O2 sensor detects ideal air-fuel ratio
Advanced control is required to reduce harmful substances (HC, CO, NOx) in exhaust gases, and the O2 sensor plays an important role in detecting the oxygen concentration in the exhaust gas and feeding it back to the ECU*1.
The NTK O2 sensor detects the oxygen concentration in the exhaust gas and feeds it back to the ECU so that the fuel-air mixture ratio (air-fuel ratio) becomes the optimal stoichiometric air-fuel ratio "λ (lambda) = 1*2". The ECU uses the signal from the O2 sensor to control the air-fuel ratio near the stoichiometric air-fuel ratio, where harmful substances in the exhaust gas are most effectively purified, by making the fuel leaner when it is rich (too much fuel) compared to the stoichiometric air-fuel ratio, and richer when it is lean (too little fuel). In this way, the NTK O2 sensor is an important component in reducing harmful substances in exhaust gases.

Specifications
【Features and Structure】
Zirconia elements have the characteristic of generating electromotive force due to differences in oxygen concentration at temperatures exceeding 300°C. Using this characteristic, zirconia-type sensors detect the difference in oxygen concentration between the inside and outside of the element (atmosphere and exhaust gas) and feed back 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 air-fuel ratio is relative to the stoichiometric air-fuel ratio. Therefore, more precise engine control is possible than with zirconia O2 sensors. It also enables engine control outside the stoichiometric air-fuel ratio (λ=1), such as lean burn control. In addition, there are 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 a integrated structure of the element and heater.
【Need for Replacement】
O2 sensors are constantly exposed to exhaust gases exceeding 600°C and accumulate combustion products, operating in a very harsh environment.
Using a deteriorated or damaged O2 sensor can lead to a number of problems.
More than 5 years or 80,000 km since new*
*Varies depending on vehicle usage.
Total length: 850mm
Total length is the length from the gasket to the tip of the connector.
Compatible manufacturer: Subaru
Compatible genuine part number: 22690-AA440

■Notes on images
*Images are for illustrative purposes only. Includes products with different sizes and colors. Product design and specifications are subject to change without notice. Please understand.

■Precautions
O2 sensors are specific to each vehicle model and engine, so they are not interchangeable 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 O2 sensor part number listed in this document.
(4) It may not function correctly if used in modified vehicles.
(5) Be careful not to drop or impact the sensor, as the internal ceramic element may break.
(6) Anti-seize compound has been applied to the threaded part of the sensor. To prevent adhesion of dirt, etc.,
remove the protective cap just before installing the sensor.
(7) Do not wipe off the anti-seize compound.
(8) If anti-seize compound gets on your hands or other body parts, wash it off immediately with water.
(9) Do not twist or bend the lead wire fixed to the main unit.
(10) Do not use an impact wrench when installing the sensor.
(11) When installing the sensor, screw it in by hand and then use a wrench to tighten it to the following approximate tightening torque.
【Part numbers starting with "LZA", "OZA", "OZR", "UAR"】:
Sensors with thread diameter 18mm, pitch 1.5mm, Hex 22mm = approx. 45-55N・m (4.5-5.5kgf・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 illuminates, before (or after) replacing the sensor, follow the service manual, etc.,
and be sure to clear (reset) the diagnostic (self-diagnosis/OBD) error codes.
Failure to clear the error codes may lead to problems such as the MIL not turning off.