A vehicle’s engine’s exhaust gases are measured for oxygen content using sensors, which are electronic devices. It also goes by the names O2 sensor and lambda sensor. The air-fuel ratio must be tuned for effective combustion and low emissions, which is why the oxygen sensor is a crucial part of the engine management system.
Based on the amount of oxygen present in the exhaust gases, the oxygen sensor generates a voltage signal. The engine control module (ECM) receives this signal and uses it to instantly modify the air-fuel ratio. Many concerns, including decreased fuel efficiency, increased emissions, and poor engine performance, might result from an sensor that isn’t working properly. As part of routine car maintenance, it is crucial to have the sensor examined and replaced if necessary.
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Types of Oxygen Sensor

Zirconia Oxygen Sensor: This sort of sensor produces a voltage signal depending on the difference in oxygen concentration between the exhaust gas and the surrounding air using a ceramic element constructed of zirconium dioxide. The voltage signal is delivered to the engine control module, which uses the reading to modify the air-fuel ratio.
Wideband Oxygen Sensor: This kind of sensor, also referred to as a lambda sensor, measures the air-fuel ratio using more sophisticated technology. Compared to the zirconia sensor, it can measure the oxygen concentration of exhaust gases over a larger range and offers a more accurate measurement. The wideband sensor can assist lower pollutants while enhancing engine performance and fuel economy.
General Problems That You Can Face
Using oxygen sensors, a number of common issues might develop:
- Contamination: Oil, coolant, and silicone are a few examples of things that might contaminate sensors and prevent them from accurately reading the oxygen levels in exhaust gas.
- Age: Oxygen sensors have a finite useful life and may degrade in accuracy over time. The normal interval between replacements is between 50,000 and 100,000 miles.
- Physical damage: Exposure to high temperatures or impacts can harm oxygen sensors, leading to sensor failure.
- Wiring problems: Damaged or disconnected cabling that connects the oxygen sensor to the engine control module may result in sensor dysfunction.
- Improper installation: The oxygen sensor may malfunction or fail too soon if it is installed incorrectly. Fuel contamination can occur on the sensor if the engine is operating too richly or too leanly, which will result in an inaccurate measurement.
Symptoms of Bad Oxygen Sensor
Reduced fuel economy: A malfunctioning oxygen sensor can make the engine run too rich or too low, which reduces fuel economy and raises fuel costs.
- Check Engine Light: One of the most typical signs of a failing sensor is the dashboard’s check engine light coming on. This light indicates that there is an issue with the oxygen sensor or the engine’s emissions system, according to the engine control module.
- Rough idling or engine misfires: Engine misfires or difficult idling can be signs of a damaged sensor. The engine may also shake or vibrate while idling. In a few instances, it can even result in engine misfires, which are sometimes felt as a lack of power or a sharp jerking.
- Engine performance issues: A sensor that isn’t working properly might make the engine run badly, with less power and acceleration.
- Increased emissions: A damaged sensor can make the engine emit more toxic gases including carbon monoxide (CO) and nitrogen oxide (NOx), which are bad for the environment and can make a car fail an emissions test.
How to Repair?
- Choose which sensor needs to be replaced: The majority of contemporary automobiles contain numerous sensors, thus it’s crucial to choose which sensor is broken before replacing it.
- Get a replacement sensor: After determining which sensor needs to be changed, buy a replacement sensor that is compatible with the make and model of your car.
- Find the sensor: Depending on the make and model of your car, you can find the sensor in a few different places. To find where the oxygen is, consult a repair manual or the owner’s manual for your car.
- Disconnect the sensor: Remove the old oxygen sensor from its mounting point by using a socket or a wrench. It might be essential to use a special sensor socket and penetrating oil to remove the sensor.
- Putting in the new sensor: The new sensor should be mounted in the proper location, and it should be torqued to the recommended level.
- Reconnect the sensor: Reconnect the new sensor’s electrical connector.
- Clear the error codes: Clear any error codes that may have been set off by the defective oxygen sensor by using an OBD-II scanner or by temporarily disconnecting the battery.
Prices of Oxygen Sensor Replacement
The price to replace an oxygen sensor varies depending on a number of variables, including the type and model of the car, where the sensor is located, and the cost of the replacement item. A sensor replacement typically costs between $100 and $400. The price might be higher in some circumstances, particularly if more repairs or services are required. Before beginning any repairs, it is generally advisable to receive a price from a skilled mechanic. Also, the price of the replacement sensor can be paid if your car is still covered by warranty.
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