NTK 25686 Air / Fuel Ratio Sensor - Upstream
OE Quality 60-Day Returns
NTK
 Direct Fit 4-Wire A/F Sensor

NTK 25686 Air / Fuel Ratio Sensor - Upstream

Brand NTK 25686
Position Upstream
Wiring Harness Length 24.5
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 · 3 vehicles

Direct-fit design. Specific-fit replacement for the correct sensor location and connector setup.

Heated sensor. Helps the sensor reach operating temperature faster for responsive exhaust feedback.

OE-focused testing. Manufactured and tested to meet or exceed OE specifications.

Cross-references Bosch 15463, DENSO Auto Parts 234-9087 and 75-4015 for the same application. See all 4.

$282.96Free 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 $282.96
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

Direct-Fit Air/Fuel Sensor

The NTK 25686 is a specific-fit heated air/fuel ratio sensor for select Mazda applications. It is built as a direct-fit 4-wire sensor with OE-style form and function for accurate exhaust feedback.

  • Specific-fit design for straightforward replacement.
  • Heated sensor construction for faster operating readiness.
  • 4-wire configuration for the correct electrical setup.
  • 18 mm thread diameter with 0.38 thread length.
  • NTK 25686 is engineered for OE-equivalent fit and performance.

Fitment and Application

Fits 2006-2008 Mazda 6, upstream. This application is listed as front sensor, located in the manifold, B1S1, California emissions, with OE-equivalent design. The NTK 25686 is a direct-fit solution for Mazda 6 models that require this specific upstream air/fuel ratio sensor.

What It Helps Address

  • Incorrect air/fuel feedback readings.
  • Check engine lights related to sensor performance.
  • Rough idle or drivability issues tied to exhaust mixture control.
  • Emissions concerns on California-emissions applications.

Installation Notes

Verify the upstream mounting location, manifold placement, B1S1 designation, and 4-wire connector match the original sensor before installation. The sensor is specific fit, so confirm thread size and harness length against the removed part. No mounting bracket is included.

Quality Assurance

NTK is a major original equipment oxygen sensor supplier and tests sensors during manufacturing to meet or exceed OE specifications. Part number 25686 reflects NTK's OE-focused design and application coverage.

Related reading

This part fits 3 vehicles
Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.
YearMakeModelTransmissionLitersCylindersPositionNotes
2008Mazda6Automatic2.3LL4UpstreamFront Sensor; Located in Manifold; B1S1; Calif. Emissions; OE Equivalent Design; Direct Fit 4-Wire A/F Sensor
2007Mazda6Automatic2.3LL4UpstreamFront Sensor; Located in Manifold; B1S1; Calif. Emissions; OE Equivalent Design; Direct Fit 4-Wire A/F Sensor
2006Mazda6Automatic2.3LL4UpstreamFront Sensor; Located in Manifold; B1S1; Calif. Emissions; OE Equivalent Design; Direct Fit 4-Wire A/F Sensor
Directly replaces or cross-references 4 part numbers
Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.
Bosch — 15463DENSO Auto Parts — 234-908775-4015L395188G1