Air–Fuel Ratio Sensor No.2 for Toyota Vehicles

This wideband AFR sensor (position No.2, downstream) keeps your engine breathing right by monitoring the exhaust mixture after the first catalyst stage. It sends precise feedback to the ECU so the system can trim fuel, lower emissions, and protect the catalytic converter. Perfect for drivers who want smooth idle, strong mid‑range torque, and clean tailpipe numbers.

Why this part is needed ⛽

Modern engines rely on exact lambda control. With accurate AFR data, the ECU optimizes injection timing and quantity, improves fuel economy, cuts NOx/HC, and prevents catalyst overheating.

How it works ⚙️

The sensor uses a heated zirconia element and a pump cell. It compares exhaust oxygen to a reference, then modulates current to hold stoichiometry. The ECU reads that current as the real-time air–fuel ratio.

What happens if it’s broken ⚠️

Expect poor mileage, hesitation, rich smell, rough idle, illuminated MIL, failed emissions, and potential catalyst damage. Prolonged driving can foul plugs and contaminate the DPF on diesel variants.

Tech tips

Install on a cold exhaust, torque to spec, avoid anti‑seize on the tip, check for exhaust leaks, and perform ECU relearn if required.

Compatible Models

• Fortuner
• Hilux