O2 Oxygen Sensor Downstream for Ford Explorer Taurus Flex (2013-2015) 3.5L

Direct-Fit Downstream O2 Sensor Set for 2013-2015 Ford Explorer, Taurus, and Flex (D3/D4 / U502)

What it Does: The Downstream Oxygen Sensor Kit monitors post-catalytic converter exhaust gas chemistry on 2013-2015 Ford Explorer, Taurus, and Flex models to maintain factory OBD-II emissions compliance and clear catalyst efficiency fault codes.

The Stock Ford Sensor Contamination and Degradation

After extensive heat cycles and mileage on the Cyclone 3.5L V6, factory downstream oxygen sensors succumb to exhaust silica contamination, carbon buildup, and internal zirconia element failure. When the OEM ceramic sensing core degrades, signal response slows, causing sluggish voltage output that triggers nuisance diagnostic trouble codes (such as P0420, P0430, or P0136). Weakened internal heater circuits also delay closed-loop readiness, skewing secondary fuel trim corrections and failing annual emissions inspections.

The Engineering Solution

This 2-piece downstream sensor set restores precise millivolt feedback to the engine control unit via robust double-wall stainless steel protective housings and rapid-response internal planar heating elements. Built with high-temperature lead wire shielding and OE-spec weather-pack pin connections, these direct-fit sensors drop directly into the post-catalyst bungs. They reliably replace failing OEM units referenced under BE5Z-9G444-A and 234-4490, ensuring instantaneous data transfer and factory-correct catalyst efficiency monitoring without wire splicing.

What's Included

• 2x Direct-Fit Downstream Oxygen Sensors

Technical Specifications

Compatibility

• 2013-2015 Ford Explorer 3.5L V6
• 2013-2015 Ford Taurus 3.5L V6
• 2013-2015 Ford Flex 3.5L V6

Frequently Asked Questions & Fitment Warnings

Does this fit the U502, D4, and D3 Explorer, Taurus, and Flex?

Yes, this is a direct fit for the 2013-2015 Ford Explorer, Taurus, and Flex equipped with the 3.5L Cyclone V6 engine in downstream (post-catalytic converter) positions only.

Are these sensors pre-threaded with anti-seize lubricant?

Threads feature factory-applied anti-seize compound or high-temp coating to prevent thread galling during exhaust bung installation.

The Ford Durability Standard

Engineered to handle severe thermal loads and daily commuter duty cycles, these direct-replacement sensors ensure long-term harness integrity and reliable PCM feedback across heavy hauling, towing, and extended highway transit.