O2 Oxygen Sensor Upstream Downstream for Honda Civic (2016-2021) 2.0L

Direct-Fit Upstream & Downstream O2 Sensors for 2016-2021 Honda Civic (FC2/FC4)

What it Does: This matched upstream and downstream oxygen sensor kit restores closed-loop fuel metering and catalyst monitoring on the 2016-2021 Honda Civic (FC2/FC4) with the K20C2 2.0L engine.

The Stock Honda Civic Sensor Failure

Over high mileage, factory O2 sensors on the FC2/FC4 Civic with the K20C2 2.0L suffer thermal shock, carbon fouling, and heater circuit burnout. Sitting in the exhaust stream, extreme heat soak degrades the upstream ceramic element and slows air-fuel feedback. Meanwhile, moisture and soot contaminate the downstream zirconia sensor, causing delayed voltage switching and triggering P0134, P0135, and P0141 fault codes.

Common Symptoms of a Failing OEM Oxygen Sensor

• Check Engine Light / DTCs: Triggers P0135 or P0141 heater faults, plus sluggish-response P0134 and P0420 codes.
• Rich Fuel Trim & Soot: Slow upstream response forces open-loop enrichment, causing black tailpipe soot.
• Poor Economy & Failed Smog: Inaccurate readings cause rough idle, hesitation, and failed emissions readiness monitors.

The Direct-Fit Dual-Sensor Oxygen Sensors Solution

Replacing both sensors together restores factory closed-loop fuel trim accuracy and eliminates response lag. Built with stainless steel housings, laser-welded protective shields, and fast-acting ceramic sensing elements, these direct-fit sensors resist heat soak and exhaust contamination. Pre-wired matched OEM-style connectors match factory harness lengths and pinouts for 234-5710, 234-8025, and 36532-5BA-A01, enabling plug-and-play installation without cutting or splicing.

What's Included

• 1 Upstream Oxygen Sensor
• 1 Downstream Oxygen Sensor

Technical Specifications

Compatibility

• 2016-2021 Honda Civic 2.0L (Confirm engine before ordering)

Frequently Asked Questions & Fitment Warnings

Does this fit the FC2/FC4 Civic?

Yes. Direct fit for the 2016-2021 Honda Civic with the K20C2 2.0L engine. Excludes 1.5L Turbo and 2.0L Turbo Type R models.

Will this clear P0135, P0141, or P0420 codes?

Yes, for sensor faults. New 234-5710 and 234-8025 units resolve P0134, P0135, and P0141 codes; a failed catalytic substrate still causes P0420.

Are OEM connectors included for plug-and-play installation?

Yes, factory-style plugs are pre-installed. Thread sensors into clean exhaust bungs using sensor-safe anti-seize only on threads, avoiding the sensing tip.

The Honda Precision Standard

Engineered for ECU fuel-trim precision and CEL-free operation on the K20C2 2.0L platform, this matched sensor kit restores emissions compliance and daily drivability for your FC2/FC4 Civic.