AIR FUEL RATIO SENSOR

Air/Fuel Ratio Sensor (Upstream) ?

This sensor is a key feedback part for modern petrol engines. It is needed to help the ECU keep the mixture close to ideal, so the engine runs clean, strong, and economical. When the mixture is right, you get smoother idle, better throttle response, and lower emissions.

How It Works ⚙️

Mounted in the exhaust stream before the catalytic converter, it “reads” oxygen content and fuel burn quality. The ECU uses this signal to fine-tune injector pulse and short/long fuel trims in real time. Its built-in heater brings the sensor up to operating temperature fast, improving cold-start control.

Why Replacement Matters ✅

A tired or failed sensor can send slow or wrong data. The ECU then over-fuels or under-fuels, causing poor mileage, rough running, hesitation, and higher emissions. Often the check engine light appears and the catalytic converter can be stressed by excess fuel ?.

Common Symptoms of a Faulty Unit

• Check engine light, mixture-related fault codes
• High fuel consumption
• Unstable idle or stumble on acceleration
• Strong fuel smell / failed emissions test

Compatibility ✅

• Outlander<Phev>