O2 Oxygen Sensor Upstream Downstream for Honda Fit (2015-2019) 1.5L

Direct-Fit Upstream & Downstream O2 Sensor Kit for 2015-2019 Honda Fit (GK5)

What it Does: This matched O2 sensor kit restores closed-loop air-fuel ratio feedback and catalyst monitoring on the 2015-2019 Honda Fit GK5 (L15B1 1.5L).

The Stock Honda Fit Oxygen Sensor Failure

Factory oxygen sensors on the GK5 Fit L15B1 1.5L endure constant thermal cycling and direct-injection soot buildup inside the exhaust stream. Over time, internal heater elements burn out or carbon fouling slows zirconia voltage response, blinding the PCM during closed-loop fueling. When switching lag or heater resistance spikes, the ECU logs fault codes like P0135, P0141, or P0171 and reverts to rich open-loop mapping.

Common Symptoms of a Failing OEM Oxygen Sensor

• Check Engine Light / DTCs: Triggers P0135, P0141 heater faults, or slow-response codes like P0133 and P0420.
• Erratic Fueling: Delayed voltage signals cause rough idling, throttle hesitation, and skewed fuel trims.
• Poor Economy & Failed Emissions: Rich default fueling wastes gas and causes OBD-II inspection failures.

The Direct-Fit Dual O2 Sensor Solution

Replacing both sensors as a matched pair restores accurate pre-cat lambda feedback and post-cat catalyst monitoring simultaneously. Built with thermal-shock-resistant zirconia ceramic sensing elements and sealed stainless steel housings, these units resist exhaust moisture and carbon fouling. Factory-length wiring harnesses with OEM-style weatherproof connectors plug straight into the GK5 harness, directly replacing 36531-5R0-003, 234-9146, and 234-4978 without cutting or splicing.

What's Included

• 1x Upstream Oxygen Sensor
• 1x Downstream Oxygen Sensor

Technical Specifications

Compatibility

• 2015-2019 Honda Fit 1.5L (GK5 / L15B1)

Frequently Asked Questions & Fitment Warnings

Does this fit the GK5 Fit?

Yes. This fits the 2015-2019 Honda Fit with the L15B1 1.5L engine. Excludes 2009-2014 GE8 models and Fit EV variants.

Will this clear P0135, P0141, or P0420 codes?

Yes, if sensor-related. Replacing both 234-9146 and 234-4978 units clears P0135/P0141 heater faults and false P0420 codes, unless the catalytic converter itself has failed.

Do the sensors require splicing or special hardware?

No. Both units use OEM-style connectors for direct installation into factory bungs; clear ECU codes afterward.

The Honda Precision Standard

Engineered for JDM fuel-injection accuracy, this matched set restores crisp throttle response and clean combustion on your GK5 for CEL-free L15B1 reliability.