The Ultimate Guide to Honda Civic Oxygen Sensors (Generations 8, 9 & 10)

If you own a Honda Civic, seeing the Check Engine Light pop up is almost a rite of passage. More often than not, the culprit is the Oxygen Sensor (O2 Sensor) or the Air-Fuel Ratio Sensor (A/F Sensor).

For many Civic owners, the confusion starts immediately:

• "Do I need Upstream or Downstream?"

• "Is it Bank 1 Sensor 1 or Sensor 2?"

• "Why does the part number change from 2011 to 2012?"

At Automotive-leader, we specialize in Honda exhaust sensors. In this guide, we will walk you through everything you need to know to diagnose and replace the O2 sensors on your 8th, 9th, and 10th Generation Honda Civic (2006–2021).

1. Know Your Civic: Which Generation Do You Drive?

Before buying parts, you must identify your generation. Honda changed the sensor technology significantly between these models.

• 8th Gen (2006–2011): The classic 1.8L engine (R18A1).

• 9th Gen (2012–2015): Updated body, but similar 1.8L engine (R18Z1) and introduction of the 2.4L Si.

• 10th Gen (2016–2021): Introduction of the 2.0L and 1.5L Turbo engines.

2. Upstream vs. Downstream: What’s the Difference?

Every Honda Civic in these years has two main sensors. Knowing which one failed is critical.

• Upstream (Sensor 1): Located before the catalytic converter (usually right on the exhaust manifold).

  • Role: On Hondas, this is often a wideband Air-Fuel Ratio Sensor. It controls fuel injection.

  • Importance: Critical for engine performance. A bad one causes poor MPG.

• Downstream (Sensor 2): Located after the catalytic converter.

  • Role: It monitors the catalytic converter's efficiency.

  • Importance: Mostly for emissions. A bad one triggers the light but rarely affects driving feel.

Still confused about Bank 1 vs Bank 2?
Since the Civic uses an inline-4 cylinder engine, it only has Bank 1.
👉 [Read More: How to Identify O2 Sensor Bank 1 and Bank 2, and Tell Upstream vs. Downstream]

3. Common Honda Civic Fault Codes

When you scan your OBDII, you will likely see these codes. Here is what they mean for your Civic:

P0134 / P0135 (Upstream Sensor Failure)

These codes usually indicate the heater circuit in your primary sensor has died. This is very common on the 2006-2011 Civic 1.8L.
👉 [Read More: How to Fix Honda Civic 1.8L Check Engine Light P0134 / P0135 (DIY Guide)] 

P0420 (Catalyst Efficiency Below Threshold)

This is the most dreaded code. While it points to a bad catalytic converter, a failing downstream O2 sensor can often give a false P0420 reading. Before spending $1000 on a converter, try changing the rear sensor first.
👉 [Read More: How to Fix Toyota/Honda P0420 Code Without Replacing the Catalytic Converter?] 

4. Find the Right Part (The "Cheat Sheet")

This is where Automotive-leader saves you time and money. Here are the exact part numbers you need for your specific model.

For 8th Gen Civic (2006–2011) 1.8L

• Problem: Poor gas mileage, P0134 code.

• The Fix: You need the Upstream Air Fuel Ratio Sensor.

• Part Number: 36531-RNA-J01 (Replaces 234-9124)
  👉 [Buy Now: 2Pcs Oxygen Sensor Set for 2007–2011 Honda Civic 1.8L] 

For 9th Gen Civic (2012–2015) 1.8L

• Problem: Check engine light, rough idle.

• The Fix: Honda updated the connector for these years.

• Part Number: 36531-RX0-A01 (Upstream) & 36532-R1A-A01 (Downstream)
  👉 [Buy Now: 2Pcs O2 Sensor Set for 2012–2015 Honda Civic / Acura ILX 2.4L] 

For 10th Gen Civic (2016–2021) 2.0L / 1.5T

• Problem: Newer models use highly sensitive wideband sensors.

• The Fix: Ensure you get the specific sensor for the 2.0L or 1.5L Turbo engine.

• Part Number: 36532-5BA-A01
  👉 [Buy Now: 2Pcs Oxygen Sensor Set for 2016–2021 Honda Civic 2.0L] 

5. Can I Install It Myself? (DIY Tips)

Absolutely. Replacing an O2 sensor on a Civic is one of the easiest DIY jobs.

1. Locate: Open the hood (for upstream) or jack up the car (for downstream).

2. Tool: You’ll need a 22mm (7/8") O2 sensor socket.

3. Spray: Use penetrating oil if the old sensor is rusted tight.

4. Swap: Unplug, unscrew, screw in the new one, plug it back in.

For a step-by-step walkthrough, check our general installation guide.
👉 [Read More: How to Install Oxygen Sensor: A Step-by-Step DIY Guide] 

6. Why Choose Automotive-leader?

Honda's ECU is notoriously picky. Cheap, generic sensors often trigger codes immediately after installation.
At Automotive-leader, our Honda-specific sensors are built to match the OEM resistance specifications.

• Direct Fit: No wire cutting or splicing.

• Warranty: 2-Year Warranty (beat that, dealership!).

• Support: Not sure? Send us your VIN.

Ready to clear that dash light?
Browse our full collection of [Honda Oxygen Sensors]  and get back on the road today.