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Denso 234-4121 Oxygen Sensor - Downstream or Upstream Right
| Brand | Denso 234-4121 |
|---|---|
| Position | Downstream |
| Connector Gender | Male |
| Mounting Type | Threaded |
| Sensor Type | Heated |
| Thread Diameter | 0.708 |
| Universal Or Specific Fit | Specific |
| Wire Quantity | 4 |
| Wiring Harness Length | 19.69 |
| Product line | OE Style |
| Fits | Kia and Mazda · 5 vehicles |
OE style replacement. Precision-built for exact replacement and a first-time fit.
Heated sensor. Helps support quicker operation and consistent emissions control.
Aluminum oxide trap layer. Protects the ceramic element for improved engine performance and longevity.
Cross-references ACDelco 213-3024, ACDelco 213-3081 and BorgWarner OS2241 for the same application. See all 16.
Denso OE Style Oxygen Sensor 234-4121
Denso 234-4121 is a heated, specific-fit oxygen sensor built to OE-style dimensions for direct replacement service. It is engineered for accurate exhaust feedback, stable engine management, and a first-time fit on select Kia Rio and Mazda Millenia applications.
Key Features
- Heated oxygen sensor for faster operating readiness
- Specific fit design for direct replacement installation
- 4-wire configuration with male connector
- Threaded mounting type with 0.708 in. thread diameter
- 19.69 in. wiring harness length
- OE Style construction from Denso
OE Style Design
Denso’s OE Style line focuses on replacement parts built to match original equipment fit and function. The 234-4121 oxygen sensor is precision built for exact replacement service, helping maintain proper exhaust monitoring on vehicles that rely on accurate sensor input for fuel control and emissions performance. This part cross-references Bosch 13894 and NTK 22120 for the same application.
Fitment
- Fits 2001-2003 Kia Rio, downstream
- Fits 2001-2002 Mazda Millenia, upstream right
What This Oxygen Sensor Helps Address
- Check engine light concerns related to oxygen sensor performance
- Incorrect air-fuel mixture feedback from a worn sensor
- Reduced fuel economy caused by delayed or inaccurate exhaust readings
- Rough idle or drivability issues tied to sensor response
- Emissions test failures caused by faulty upstream or downstream sensing
Installation Notes and Tips
Verify connector style, thread diameter, and harness length before installation. This Denso oxygen sensor uses a threaded mounting design and a 4-wire male connector, so matching the original sensor layout is important for proper routing and secure fitment. Confirm whether your vehicle requires a downstream or upstream right sensor before ordering.
Quality Assurance
Denso manufactures and tests this sensor to OE standards, with attention to precise fit and consistent operation. The design includes an aluminum oxide trap layer that helps protect the ceramic element from silicone and lead contamination, supporting long service life and stable engine performance.
| Year | Make | Model | Position | Notes |
|---|---|---|---|---|
| 2003 | Kia | Rio | Downstream | OE Style |
| 2002 | Kia | Rio | Downstream | OE Style |
| 2002 | Mazda | Millenia | Upstream Right | OE Style |
| 2001 | Kia | Rio | Downstream | OE Style |
| 2001 | Mazda | Millenia | Upstream Right | OE Style |
| No rows match your filter. | ||||