The oxygen (O2) sensor monitors the level of oxygen in the exhaust gases and sends this data to the engine control unit (ECU). The ECU uses this information to adjust the air-fuel mixture for optimal performance and emissions. If the oxygen sensor fails, it can cause poor fuel economy, rough running, and higher emissions. Replacing a faulty O2 sensor restores proper engine efficiency.

What is an oxygen sensor replacement?

This service involves removing the faulty oxygen sensor and installing a new one. Vehicles typically have multiple sensors, located before and after the catalytic converter, so replacement may involve one or more sensors depending on the fault.

Why do you need an oxygen sensor replacement?

A failing O2 sensor sends incorrect readings to the ECU, causing the engine to run too rich or too lean. This results in poor performance, increased fuel consumption, and potential damage to the catalytic converter.

Common signs you need an oxygen sensor replacement

• Check Engine Light illuminated with O2 sensor fault codes
• Poor fuel economy
• Rough idle or engine misfires
• Increased exhaust emissions or failed emissions test
• Loss of power or poor acceleration

What happens during an oxygen sensor replacement?

A mechanic will:

1. Scan the ECU for fault codes to confirm which sensor has failed
2. Inspect the exhaust system and wiring for damage
3. Remove the faulty O2 sensor
4. Install a new oxygen sensor of the correct type
5. Clear ECU fault codes
6. Test drive the vehicle to confirm proper operation

How much does an oxygen sensor replacement cost?

Replacement typically costs $250–$450 per sensor, depending on the vehicle and sensor location. Some vehicles with multiple sensors may cost more if more than one needs replacing.

Is it unsafe to drive with a faulty oxygen sensor?

While the car may still run, a faulty O2 sensor increases fuel consumption, emissions, and the risk of catalytic converter damage. It can also cause poor drivability. Replacement is recommended as soon as possible.