---
product_id: 18724666
title: "Denso 234-9123 Oxygen Sensor (Air And Fuel Ratio Sensor), Regular (2349123)"
brand: "denso"
price: "$396.56"
currency: USD
in_stock: true
reviews_count: 12
category: "Denso"
url: https://www.desertcart.ec/products/18724666-denso-234-9123-oxygen-sensor-air-and-fuel-ratio-sensor
store_origin: EC
region: Ecuador
---

# Optimizes fuel efficiency Operates up to 800°C Universal thread-in fit Denso 234-9123 Oxygen Sensor (Air And Fuel Ratio Sensor), Regular (2349123)

**Brand:** denso
**Price:** $396.56
**Availability:** ✅ In Stock

## Summary

> ⛽ Upgrade your ride’s brain — smarter fuel, smoother drive, zero compromises!

## Quick Answers

- **What is this?** Denso 234-9123 Oxygen Sensor (Air And Fuel Ratio Sensor), Regular (2349123) by denso
- **How much does it cost?** $396.56 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.ec](https://www.desertcart.ec/products/18724666-denso-234-9123-oxygen-sensor-air-and-fuel-ratio-sensor)

## Best For

- denso enthusiasts

## Why This Product

- Trusted denso brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Durability Under Fire:** Constructed with stainless steel and zirconium to withstand extreme exhaust temperatures up to 800°C.
- • **Fuel-Savvy Sensor Tech:** Zirconia solid electrolyte ensures accurate air/fuel ratio detection, maximizing mileage and power.
- • **Precision OE Performance:** Engineered to meet strict OEM standards for flawless first-time fit and function.
- • **Plug & Play Universal Fit:** Thread-in mounting designed for seamless replacement across multiple Subaru and Saab models.
- • **Emission & Engine Health Guardian:** Keeps catalytic converter life longer by maintaining optimal air-fuel mixture and reducing harmful emissions.

## Overview

The Denso 234-9123 Oxygen Sensor is a high-precision air/fuel ratio sensor built with durable zirconia and stainless steel materials. Designed as a universal thread-in replacement for select Subaru and Saab models, it operates reliably at temperatures up to 800°C. This sensor optimizes engine performance and fuel efficiency by continuously monitoring exhaust gas composition, ensuring cleaner emissions and extended catalytic converter life. Trusted OEM quality means a perfect fit and lasting durability, making it the go-to upgrade for savvy drivers aiming to keep their engines running smooth and efficient.

## Description

Denso part number 234-9123 is a replacement air/fuel ratio sensor for 2006 Saab 9-2X, 2006-2010 Subaru Forester, 2006-2011 Subaru Impreza, 2006-2009 Subaru Legacy, and 2006-2009 Subaru Outback vehicles.Denso Air/Fuel Ratio Sensors are manufactured and tested to the strictest OE standards for unparalleled performance. Each component is precision-built for exact replacement, and a first time fit. The superior design of Denso Air/Fuel Ratio Sensors maximizes engine performance and fuel efficiency while reducing fuel consumption and harmful emissions. Denso Air/Fuel Ratio Sensors increase performance by mapping air/fuel ratios throughout the RPM range. They also reduce emissions by keeping the air-fuel mixture at an optimum ratio. Optimal air/fuel ratios reduce fuel consumption and maximize catalytic converter life. Denso gives you the right part and the right fit, the first time..

Review: Worked great on my EJ253! - I own a 2008 5MT Outback with over 200k. The car has been fantastic. For the last couple years I've been getting a random "Catalyzer below threshold" code. I thought it was time to replace the cat converter (not surprising giving the miles). But I decided to try the anti fouler bung on the O2 sensor. It worked for a while, but my check engine light kept coming back while in the highway, disabling my cruise control (some "lean condition" code. On these Subarus, and many newer cars, the downstream sensor (after the converter), is not only to check the efficiency of the converter but also has something to do with the fuel trim). I finally decided to replace both O2 sensors (the car well deserves new sensors after all these years), and sure enough, the check engine light has not returned, engine runs smoother, and I should expect some improvement in the fuel mileage. So, if you're on the same boat, replacing both O2 sensors quite probably will do the trick, and it's way cheaper than the catalytic converter. One last thing....as many people before me pointed out...don't use cheaper sensors. These Denso ones are OEM, and work fine.
Review: Go only with Denso- oem supplier to subaru - it fit perfectly as far as the connector was identical oem. you want to only go with denso which is the oem supplier for subaru. price from this vendor is great, best i have seen anywhere. new at oreilly etc was $50 more cost! ck engine lite went out immed, car runs so much better as this going bad really messes up the fuel mixture- makes car run rich, so gas mileage is better and it runs way better, more power etc. this is the upstream 02 sensor, which is the one that takes the worst beating of the two 02 sensors in any vehicle. it should be replaced about every 80k miles, the downstream one can go longer. funny but my ck engine lights just got thrown, runs fine but something threw that, could be downstream sensor but car only has 90k miles so it should not be going bad this soon. supposed to go like 150k or more even because its downstream of the catalytic converter so it gets cleaner air and doesnt go down as fast as upstream which gets raw untreated exhaust. i did a ohm test on downstream and it was in spec, i did upstream prior to replacement and it was showing out of spec. ck engine analysis cemented the fact it needed replacement at about 90k mi, but actually the lite was throwing at about 84k. newer subarus are more sensitive to sensors, mine is a 2010. 2008 and older are not nearly as effected by sensor health as 2009 and newer.

## Features

- Efficient Fuel Consumption
- Constructed from durable material
- Features zirconia solid electrolyte
- Manufactured to detect the amount of exhaust gas air fuel ratio
- Fit type: Universal Fit

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B001F7EK44 |
| Batteries Included? | No |
| Batteries Required? | No |
| Best Sellers Rank | #156,666 in Automotive ( See Top 100 in Automotive ) #563 in Automotive Replacement Oxygen Sensors |
| Brand | Denso |
| Color | Regular |
| Customer Reviews | 4.6 4.6 out of 5 stars (507) |
| Date First Available | January 2, 2007 |
| Global Trade Identification Number | 00042511115347 |
| Included Components | Air/Fuel Ratio Sensor |
| Is Discontinued By Manufacturer | No |
| Item Package Quantity | 1 |
| Item Weight | 4 ounces |
| Item dimensions L x W x H | 5.75 x 2.19 x 1.88 inches |
| Item model number | 234-9123 |
| Manufacturer | DENSO |
| Material | Stainless Steel, Zirconium |
| Mounting Type | Thread-In |
| Output Type | NPN |
| Part Number | 234-9123 |
| Product Dimensions | 5.75 x 2.19 x 1.88 inches |
| Specific Uses For Product | Replacement Air/Fuel Ratio Sensor |
| Style | Replacement Part |
| UPC | 042511115347 |
| Upper Temperature Rating | 800 Degrees Celsius |
| Warranty Description | Manufacturer Warranty |

## Product Details

- **Brand:** Denso
- **Item Weight:** 4 ounces
- **Item dimensions L x W x H:** 5.75 x 2.19 x 1.88 inches
- **Material:** Stainless Steel, Zirconium
- **Style:** Replacement Part

## Images

![Denso 234-9123 Oxygen Sensor (Air And Fuel Ratio Sensor), Regular (2349123) - Image 1](https://m.media-amazon.com/images/I/51ycWL8hDuL.jpg)
![Denso 234-9123 Oxygen Sensor (Air And Fuel Ratio Sensor), Regular (2349123) - Image 2](https://m.media-amazon.com/images/I/51WFtdeC+4L.jpg)
![Denso 234-9123 Oxygen Sensor (Air And Fuel Ratio Sensor), Regular (2349123) - Image 3](https://m.media-amazon.com/images/I/51DgO2AwgeL.jpg)

## Questions & Answers

**Q: Is this compatible to the subaru oem part # 22641aa36a?**
A: I don't know how this part relates to any Subaru part numbers.
I installed this on a 2007 Outback with a 2.5 L SOHC engine; the engine has run fine since installation and the MIL has not lit.
As I stated in my review, the plug end was different than the original part, so I had to splice the original plug onto this sensor.
I checked and double-checked the part number, and this one comes up as the correct part, so perhaps my car was built with an oddball plug.
If your car has the same plug as mine and you don't want to splice it, it may be worthwhile for you to get a sensor from Subaru.

**Q: Anyone know where i can get an extension for this o2 sensor: denso 234-9123 oxygen sensor**
A: Spark plug anti-foul extenders are sometimes used as downstream O2 sensor extenders to "fix" PO420 codes, and are available here and in parts stores. 

The thread size and pitch, for this application should be M18 X 1.5. You need to drill out the end. 

This trick can work for downstream sensors on some vehicles, but I doubt it will work for upstream sensors. It may cause error codes and also cause the engine to run poorly because the sensor will receive inaccurate information about the oxygen concentration in the exhaust and thereby cause the fuel air mix to deviate from the correct stoichiometric ratio.

I'm just a home mechanic, so take my words with an appropriate sized grain of salt, but that is what makes sense to me based on my knowledge. If the upstream sensor is bad it should be replaced. If the sensor is good but the problem is with the engine, it is best to address the root cause of the problem.

**Q: Camshift actuator sensor location**
A: What kind of car?   Usually located on head near the back of camshaft.

**Q: I got a P0172 code ( system too rich bank 1) on my 2009 subaru impreza anesis 1.5L what is the problem ?**
A: Engine running too rich could come from many things, so if you have the knowledge, tools and time it is better to address the problem methodically rather than buying parts and hoping for the best. It could be a leaky vacuum hose, dirty throttle throttle body, dirty IACV (if the car has it), bad MAP sensor, leaky exhaust system, worn spark plugs, bad oxygen sensor, perhaps even misfire from a bad coil. In my opinion the oxygen sensor is not high on the list, and is among the more expensive possible culprits. If you don't want to or can't do the troubleshooting, it may be best to take the car to a competent mechanic.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Worked great on my EJ253!
*by A***R on November 12, 2024*

I own a 2008 5MT Outback with over 200k. The car has been fantastic. For the last couple years I've been getting a random "Catalyzer below threshold" code. I thought it was time to replace the cat converter (not surprising giving the miles). But I decided to try the anti fouler bung on the O2 sensor. It worked for a while, but my check engine light kept coming back while in the highway, disabling my cruise control (some "lean condition" code. On these Subarus, and many newer cars, the downstream sensor (after the converter), is not only to check the efficiency of the converter but also has something to do with the fuel trim). I finally decided to replace both O2 sensors (the car well deserves new sensors after all these years), and sure enough, the check engine light has not returned, engine runs smoother, and I should expect some improvement in the fuel mileage. So, if you're on the same boat, replacing both O2 sensors quite probably will do the trick, and it's way cheaper than the catalytic converter. One last thing....as many people before me pointed out...don't use cheaper sensors. These Denso ones are OEM, and work fine.

### ⭐⭐⭐⭐⭐ Go only with Denso- oem supplier to subaru
*by J***S on October 29, 2017*

it fit perfectly as far as the connector was identical oem. you want to only go with denso which is the oem supplier for subaru. price from this vendor is great, best i have seen anywhere. new at oreilly etc was $50 more cost! ck engine lite went out immed, car runs so much better as this going bad really messes up the fuel mixture- makes car run rich, so gas mileage is better and it runs way better, more power etc. this is the upstream 02 sensor, which is the one that takes the worst beating of the two 02 sensors in any vehicle. it should be replaced about every 80k miles, the downstream one can go longer. funny but my ck engine lights just got thrown, runs fine but something threw that, could be downstream sensor but car only has 90k miles so it should not be going bad this soon. supposed to go like 150k or more even because its downstream of the catalytic converter so it gets cleaner air and doesnt go down as fast as upstream which gets raw untreated exhaust. i did a ohm test on downstream and it was in spec, i did upstream prior to replacement and it was showing out of spec. ck engine analysis cemented the fact it needed replacement at about 90k mi, but actually the lite was throwing at about 84k. newer subarus are more sensitive to sensors, mine is a 2010. 2008 and older are not nearly as effected by sensor health as 2009 and newer.

### ⭐⭐⭐⭐⭐ A good deal on OEM sensor for a Subaru.
*by F***R on September 11, 2017*

I bought this as an upstream sensor for 2007 Subaru with a 2.5 liter engine to replace an original after 225,000 miles. It came with some copper anti-seize compound. It looked like the original with one important exception-the wire connector was different than the original one in my car. I checked the part number several times, and even ordered another one from my local parts store to check it-the numbers match but the connector is different. Perhaps there was a change made after my car was made. Because I needed to get my car back together, I cut the connectors off and swapped my original onto the new sensor-the wires are the same, so it was just a minor challenge, but cutting into an expensive part made me nervous. The sensor has worked well-no check engine light, and the scanner showed fast response and good fuel trims. After almost 6 months and more than 10,000 miles, this is still working. There have been no error codes, fuel mileage is what I would expect and the engine runs great. Update. Almost 2 years later the engine is still running strong, good fuel trim, no sensor-related check engine light. Update. I got another one of these for another car, and in the process learned why I thought the connector was wrong. It has a plastic protective piece that I thought was part of the connector itself. Removal of the piece revealed the correct connector. That was a critical thinking problem on my part, and realizing the error of my ways has hopefully made me a better person in some small way.

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*Product available on Desertcart Ecuador*
*Store origin: EC*
*Last updated: 2026-02-26*