HTMXJA Oxygen O2 Sensor Pair for Hyundai/Kia 2.4L L4 — Upstream 234-5055 & Downstream 234-4568, OE Fitment

High-precision replacement oxygen sensors (upstream 234-5055 and downstream 234-4568) engineered to restore accurate air-fuel monitoring and emissions performance on 2012–2017 Accent, 2012–2018 Rio, 2012–2016 Soul and compatible Veloster 2.4L engines.

These two HTMXJA oxygen sensors — one upstream and one downstream — are designed to match OE fitment and function for L4 2.4L Hyundai/Kia applications. Each sensor uses materials and connectors that align with original equipment specifications so installation is straightforward and no vehicle modifications are required. Replacing failing or aging sensors helps the engine management system read exhaust oxygen levels correctly, which supports steady operation and consistent fuel-system feedback.

How will these sensors affect my vehicle's performance?

Fresh oxygen sensors provide reliable voltage and resistance signals to the engine control unit (ECU), which helps maintain correct air-fuel ratios. That consistent feedback prevents long-term drivability issues tied to incorrect fueling adjustments.

• Upstream sensor (OE# 234-5055) monitors combustion conditions before the catalytic converter.
• Downstream sensor (OE# 234-4568) checks emissions after the catalytic converter.
• Accurate readings reduce engine hesitation and irregular idle caused by bad sensor data.

Are these HTMXJA sensors compatible with my car?

They are manufactured to match OEM specifications for specific Hyundai and Kia 2.4L L4 models. Confirm fit by comparing OE part numbers and connector/pigtail length prior to purchase to ensure exact compatibility.

• Fitment: Accent 2012–2017 L4-2.4L; Rio 2012–2018 L4-2.4L; Soul 2012–2016 L4-2.4L; compatible Veloster models using the same engine.
• Reference part numbers included for cross-checking: 234-5055, 234-4568, 2345055, 2344568.
• Also cross-references many OE numbers listed in the product details for easy verification.

What should I expect during installation and maintenance?

These sensors are built for a straightforward swap with OEM-style threads, connector types, and heat shielding. Basic hand tools and a suitable oxygen sensor socket are typically all that’s needed for replacement.

• Designed for plug-and-play replacement with original connectors and mounting thread pattern.
• No vehicle modifications required when match-checked against OE specs and harness length.
• Six-month limited warranty; inspect wiring and harness routing during installation.

How do I know when to replace the upstream or downstream sensor?

Replace sensors if you see a persistent check engine light related to O2 sensor codes, poor fuel economy, rough idle, or failed emissions tests. Visual damage, corrosion on the connector, or wiring faults also warrant replacement.

• Error codes P0130–P0167 (or similar) often indicate upstream/downstream O2 sensor issues.
• Observe sensor response time and voltage swing during diagnostics to confirm function.
• Replace both sensors as a pair when applicable to ensure balanced readings and long-term reliability.

Who is this for: HTMXJA’s 2-piece oxygen sensor kit is aimed at DIY mechanics, independent shops, and vehicle owners who need direct-fit upstream and downstream replacements for Hyundai/Kia 2.4L L4 models. It’s appropriate for anyone verifying OEM part numbers and seeking a cost-effective, OEM-spec alternative to restore accurate emissions sensing and fuel-system feedback.