Honda FK8 Civic Type R Oxygen (O2) Sensor 36531-RPY-G02

Genuine Honda Upper Oxygen Sensor (36531-RPY-G02) - 2017-2021 Civic Type R

The upper O2 sensor is what tells your ECU whether the engine is running rich or lean, and everything about how the car meters fuel depends on that signal being accurate. When it goes lazy, you don't get a dramatic failure, you get worse fuel economy, a check engine light, and an ECU working from bad information. This is the genuine Honda replacement for the FK8.

Upper, Not Lower

Quick check before ordering, since the FK8 has both.

This is the upper sensor, also called the upstream or primary sensor. It sits ahead of the catalytic converter and it's the one your ECU uses for fuel control.

The lower sensor sits after the cat and primarily monitors catalyst efficiency. Different part, different job. If your code points downstream, this isn't the sensor you need.

What A Failing Sensor Looks Like

Worth knowing, because these degrade rather than simply stopping.

The usual signs are a check engine light with an O2 sensor or fuel trim code, worse fuel economy than the car normally returns, and sometimes a rough idle or hesitation as the ECU corrects against a signal it can't trust.

What makes it frustrating is that a slow sensor still reads. It just reads late, which means your fuel trims are chasing a signal that's behind what's actually happening in the exhaust. The car runs, it just doesn't run right, and the symptoms are vague enough to get blamed on other things.

It Matters More On A Tuned Car

Worth calling out, since most FK8s are running something.

If your car is tuned, your tuner set fueling based on what the sensor was reporting at the time. A sensor that's drifted since then means the ECU is correcting against bad data, which undermines the tune you paid for.

On a boosted engine that's not just a fuel economy question. Accurate air-fuel readings are part of what keeps the engine safe under load, and a lazy sensor is a poor thing to rely on when you're leaning on the car.

If you're planning dyno time, replacing a questionable sensor beforehand is worth doing. Your tuner will be working from clean data rather than trying to account for a sensor they can't verify.

Use The Genuine Sensor

O2 sensors are a spot where aftermarket quality varies enormously, and the failure mode isn't obvious.

A cheap sensor may read, but reading slowly or drifting over time produces exactly the vague running problems you were trying to fix. You end up chasing a fault you introduced.

This is the exact part Honda spec'd for the FK8, with the correct response characteristics the ECU expects. On a component this central to how the engine runs, it's not worth economizing.

Fitment

2017-2021 Honda Civic Type R (FK8)
2021 Honda Civic Type R Limited Edition

Part number 36531-RPY-G02. Upper sensor.

Who Should Grab One

This is for the Type R owner chasing a check engine light or fuel economy that's fallen off, and for anyone heading to a dyno who'd rather start with a sensor they trust. It's a straightforward part doing an important job, and the genuine one is what your ECU was calibrated around. Swap it, clear your codes, and get back to accurate fueling.

Fits: 2017-2021 Honda Civic Type R and 2021 Civic Type R Limited Edition. Part number: 36531-RPY-G02. Type: genuine Honda upper (upstream) oxygen sensor.