What is the part number of the oxygen sensor on a Toyota Corolla?

There is no single part number that covers all Toyota Corolla oxygen sensors. The correct number depends on your car's year, engine, and whether you need the upstream (pre-cat) or downstream (post-cat) sensor.

To get the exact part number, identify your Corolla's year and engine, determine which O2 sensor you need, and then consult VIN-based parts catalogs or a dealer to confirm the OE number or a trusted aftermarket equivalent.

Why part numbers vary across Corolla generations

Over the years Toyota redesigned exhaust and sensor assemblies, so different generations use different oxygen sensor part numbers even for similar engines. The sensor location (upstream vs downstream) and the number of sensors can also change between trims and markets.

Sensor location and types

In most Corolla generations, you will have at least two sensors on the exhaust: upstream sensor 1 before the catalytic converter and downstream sensor 2 after the catalytic converter. Some engines or configurations may introduce additional sensors or heated variants with different connectors.

How to find the right part number for your Corolla

Use the steps below to identify the exact part number for your O2 sensor.

• Identify whether you need the upstream (pre-cat) sensor or the downstream (post-cat) sensor based on your symptoms or the sensor's location on the exhaust.


• Note your Corolla's model year and engine code (for example, a 1.8L engine such as 2ZR-FE/2ZR-FAE in newer generations).


• Locate the VIN and use a VIN-based parts catalog or contact a dealer to pull the exact OE part number for your vehicle.


• Inspect the sensor housing or connector for stamped numbers or codes that reveal the exact replacement part.


• Cross-check the OEM part number with reputable catalogs from Toyota, Denso, NTK, or your chosen retailer to ensure a correct match.

Following these steps will help you order the correct oxygen sensor for your Corolla's year and engine configuration.

Verifying compatibility and sourcing

When shopping, use the OE part number or a reliable cross-reference to confirm fitment. If in doubt, contact a dealership or use a parts retailer’s live support and provide your VIN to ensure the part is correct.

• Access the official Toyota parts catalog or dealer site and input your VIN to obtain the exact OE oxygen sensor number.


• Cross-reference with Denso or NTK (or other reputable aftermarket brands) and verify connector type, thread size, and whether the sensor is heated.


• Confirm you are selecting upstream (sensor 1) versus downstream (sensor 2) based on the needed location.


• Verify the sensor’s thread size and electrical connector compatibility to avoid installation issues.

These verification steps help ensure you receive the exact oxygen sensor your Corolla requires.

Summary

In short, there isn’t a universal oxygen sensor part number for Toyota Corolla models. The right number depends on the model year, engine, and whether the sensor is upstream or downstream. Use your VIN and engine information to pull the precise OE number from Toyota's catalogs or trusted retailers, and confirm fitment with the sensor’s physical specifications before purchasing.

How much is an O2 sensor for a Toyota Corolla?

The average cost for a Toyota Corolla Oxygen Sensor Replacement is between $490 and $583.

How do I know which O2 sensor I have?

You can identify oxygen (O2) sensors by locating them in the exhaust system, typically in or before the catalytic converter. They can also be identified by their number of wires (narrowband sensors usually have up to four, while wideband sensors have more). For specific identification, you can use a diagnostic tool to read codes, or physically inspect the sensor and its wiring in the exhaust system. 
This video explains how to locate O2 sensors and distinguish between bank and sensor numbers: 58sYOUCANICYouTube · Dec 14, 2023
Physical and location-based identification

• Location: Find the O2 sensors screwed into the exhaust pipe, usually with one sensor before the catalytic converter ("upstream") and one or more after it ("downstream"). 
• Engine type: On a four-cylinder engine, there's usually only one bank (Bank 1), so you'll find Bank 1 Sensor 1 (upstream) and Bank 1 Sensor 2 (downstream). 
• V-type engines: V6 or V8 engines have two banks, so you'll have a Bank 1 and a Bank 2, each with an upstream ("Sensor 1") and a downstream ("Sensor 2") sensor. 
• Wire count: Narrowband sensors typically have four wires or fewer, while wideband sensors generally have more than four wires. 

This video shows the locations of upstream and downstream O2 sensors: 55s1A Auto: Repair Tips & Secrets Only Mechanics KnowYouTube · May 12, 2017
Technical identification

• Diagnostic tool: Connect a diagnostic scan tool to your car's ODB-II port. It can read fault codes that point to a specific sensor and show live data for each one, making it easier to confirm which is failing. 
• Multimeter test: For a functional test, you can use a multimeter set to DC volts to check the signal wire on a running engine. A healthy sensor's voltage should fluctuate between 0.10.10.1V and 0.90.90.9V. A steady reading or a value outside this range indicates a problem. 

This video demonstrates how to test an oxygen sensor with a multimeter: 59sBlueDriverYouTube · Apr 25, 2022

How many oxygen sensors are in a Toyota Corolla?

A Toyota Corolla typically has two O2 sensors: one upstream (before the catalytic converter) and one downstream (after the catalytic converter). Modern vehicles require these sensors to monitor the air-fuel mixture and check the efficiency of the catalytic converter.
 

• Upstream O2 sensor: Located before the catalytic converter, it monitors the exhaust gases to help the engine computer adjust the air-fuel ratio for optimal performance. 
• Downstream O2 sensor: Located after the catalytic converter, it measures the effectiveness of the catalytic converter by checking the emissions after they have been treated. 
• Multiple sensors: Some models may have a different number of sensors depending on the engine and year, but two is the most common setup. For example, vehicles with two catalytic converters or more complex exhaust systems may have up to four sensors. 

What is part number 234 4355?

Denso part number 234-4355 is a replacement oxygen (O2) sensor for 2003-2006 Acura MDX, 2005-2008 Acura RL, 2004-2006 Acura TL, 2003-2007 Honda Accord, 2003 Honda Civic, 2005-2010 Honda Odyssey, 2005-2008 Honda Pilot, and 2006-2008 Honda Ridgeline vehicles.