Ford OEM – (Rear) O₂ Sensor for 2013-2018 Focus ST

Ford OEM – (Rear) O₂ Sensor for 2013-2018 Focus ST

If you’ve already upgraded to a catless downpipe and fixed your upstream O2 reading issues, don’t forget the downstream O2 sensor. This is the sensor after the catalytic converter (or what would have been the cat) that tells your ECU how well the exhaust system is working. Running without a proper downstream sensor can cause bogus CEL codes, false emissions feedback, erratic tuning behavior, and even poor idle or AFR data because it’s still trying to monitor what used to be the converter’s efficiency.

This genuine Ford OEM downstream oxygen sensor is a direct fit for the 2013-2018 Focus ST 2.0 EcoBoost and restores correct post-cat air/fuel monitoring so your ECU can make accurate decisions. Whether you’re on stock exhaust or fully modified, this part helps keep your engine running cleanly without unnecessary fault codes or tune confusion.

Key Features

• Direct factory fit: Designed specifically for Focus ST 2013-2018, plug-and-play with the proper connector and harness length.

• Accurate post-cat monitoring: Reestablishes correct downstream oxygen sensing so your ECU gets reliable emissions data.

• Reduces false CELs: Helps prevent check engine lights and erroneous diagnostic codes tied to downstream O2 misreads.

• OEM reliability: Genuine Ford engineering built for durable performance in hot exhaust conditions.

• Essential for tuned cars: On catless setups and performance exhausts, the downstream sensor still needs to talk to your ECU for stable tuning.

Application

Fits Ford Focus ST 2013-2018 2.0 EcoBoost as the downstream (secondary) oxygen sensor after the catalytic converter.

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