Introduction
The Oxygen Sensor measures how much oxygen is in the exhaust gases. This helps the engine adjust the air-fuel mixture for best performance and fuel economy.
Where Is the O2 Sensor Located?
Usually:
- One sensor before the catalytic converter
- One sensor after the catalytic converter
What It Does
- Helps engine achieve correct air-fuel ratio
- Improves engine power
- Controls emissions
- Saves fuel
Symptoms of a Faulty O2 Sensor
- Check Engine Light on
- High fuel consumption
- Rough engine idle
- Engine hesitation
- Failed emissions test
Replacement Interval
Most O2 sensors last 100,000–150,000 km.
Why It Matters
A bad O2 sensor can damage the catalytic converter and increase fuel consumption by 20–30%.