NTK 25669 Air / Fuel Ratio Sensor - Upstream
OE Quality 60-Day Returns
NTK
 Direct Fit 4-Wire A/F Sensor

NTK 25669 Air / Fuel Ratio Sensor - Upstream

Brand NTK 25669
Position Upstream
Wiring Harness Length 18.0
Sensor Type Heated
Thread Length 0.38
Universal Or Specific Fit Specific
Wire Quantity 4
Thread Diameter 18.000
Mounting Bracket Included No
Product line Direct Fit 4-Wire A/F Sensor
Fits Mazda · 11 vehicles

Direct fit. Specific-fit sensor for straightforward replacement and installation.

Heated sensor. Helps the sensor reach operating temperature quickly for reliable performance.

OE specifications. Extensively tested to meet or exceed original equipment standards.

Cross-references DENSO Auto Parts 234-9085, Quality-Built 15918 and 75-3493 for the same application. See all 5.

$159.68Free shipping
In stock · usually ships same day before 1pm CST
Step 1 — Confirm fitment
Free return shipping if it doesn't fit when you check fitment here first.

Select your vehicle to confirm fitment
Verify this part fits before purchasing — free returns if it doesn't
Step 2 — Quantity
Order total $159.68
Free shipping to the continental U.S.
Free returns within 60 days if it doesn't fit when fitment is verified.
Not what you need? See all Air / Fuel Ratio Sensor options

NTK Direct Fit Air/Fuel Ratio Sensor

NTK 25669 is a direct fit, heated 4-wire air/fuel ratio sensor for specific Mazda applications. It is built for upstream, front sensor placement in the manifold and supports California emissions-equipped vehicles with OE-equivalent design.

Key Features

  • Direct fit replacement for specific Mazda 3 and Mazda 3 Sport applications
  • Heated sensor design for faster operating temperature
  • 4-wire configuration for factory-style electrical connection
  • 18.0 in. wiring harness length
  • 18.000 mm thread diameter with 0.38 in. thread length
  • Specific fit application for upstream, front sensor location
  • No mounting bracket included

Product Details

NTK is the Sensor Specialist and a major original equipment oxygen sensor manufacturer, with ceramic-based sensor production and manufacturing controls that support consistent fit, form, and function. Part number 25669 is engineered as an OE-equivalent direct fit air/fuel ratio sensor for 2004-2009 Mazda 3 and 2009 Mazda 3 Sport models in the upstream position. This part cross-references DENSO Auto Parts 234-9085 for the same application.

Common Issues This Sensor Can Address

  • Check engine light related to air/fuel ratio sensor performance
  • Rough idle caused by inaccurate upstream sensor readings
  • Fuel trim concerns from a slow or failing front sensor
  • Emissions test failure tied to sensor response or signal quality
  • Driveability issues on Mazda 3 and Mazda 3 Sport models with California emissions

Installation Notes

Verify the upstream, front sensor location before ordering. This NTK 25669 sensor is specific fit and uses a factory-style 4-wire connection, so matching the connector and thread specifications is important. Confirm manifold mounting, thread diameter, and harness length against the original sensor on the vehicle.

Quality Assurance

NTK manufactures oxygen and air/fuel ratio sensors with extensive testing during production to help ensure quality and reliability that meet or exceed OE specifications. The brand’s OE application focus and ceramic sensor expertise support consistent replacement performance for Mazda 3 and Mazda 3 Sport applications.

Related reading

This part fits 11 vehicles
Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.
YearMakeModelLitersCylindersPositionNotes
2009Mazda32.3LL4UpstreamFront Sensor; Located in Manifold; B1S1; Calif. Emissions; OE Equivalent Design; Direct Fit 4-Wire A/F Sensor
2009Mazda32.0LL4UpstreamFront Sensor; Located in Manifold; B1S1; Calif. Emissions; OE Equivalent Design; Direct Fit 4-Wire A/F Sensor
2009Mazda3 Sport2.0LL4UpstreamFront Sensor; Located in Manifold; B1S1; Calif. Emissions; OE Equivalent Design; Direct Fit 4-Wire A/F Sensor
2008Mazda32.3LL4UpstreamFront Sensor; Located in Manifold; B1S1; Calif. Emissions; OE Equivalent Design; Direct Fit 4-Wire A/F Sensor
2008Mazda32.0LL4UpstreamFront Sensor; Located in Manifold; B1S1; Calif. Emissions; OE Equivalent Design; Direct Fit 4-Wire A/F Sensor
2007Mazda32.3LL4UpstreamFront Sensor; Located in Manifold; B1S1; Calif. Emissions; OE Equivalent Design; Direct Fit 4-Wire A/F Sensor
2007Mazda32.0LL4UpstreamFront Sensor; Located in Manifold; B1S1; Calif. Emissions; OE Equivalent Design; Direct Fit 4-Wire A/F Sensor
2006Mazda32.3LL4UpstreamFront Sensor; Located in Manifold; B1S1; Calif. Emissions; OE Equivalent Design; Direct Fit 4-Wire A/F Sensor
2006Mazda32.0LL4UpstreamFront Sensor; Located in Manifold; B1S1; Calif. Emissions; OE Equivalent Design; Direct Fit 4-Wire A/F Sensor
2005Mazda32.0LL4UpstreamFront Sensor; Located in Manifold; B1S1; Calif. Emissions; OE Equivalent Design; Direct Fit 4-Wire A/F Sensor
2004Mazda32.0LL4UpstreamFront Sensor; Located in Manifold; B1S1; Calif. Emissions; OE Equivalent Design; Direct Fit 4-Wire A/F Sensor
Directly replaces or cross-references 5 part numbers
Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.
DENSO Auto Parts — 234-9085Quality-Built — 1591875-3493LF63188G1B9USG1661