Denso 234-9121 Air / Fuel Ratio Sensor - Upstream
OE Quality 60-Day Returns
Denso
 OE Style

Denso 234-9121 Air / Fuel Ratio Sensor - Upstream

Brand Denso 234-9121
Position Upstream
Grade Type Regular
Sensor Type Heated
Universal Or Specific Fit Specific
Wire Quantity 4
Wiring Harness Length 37.80
Product line OE Style
Fits Subaru · 3 vehicles

OE style replacement. Precision-built for exact replacement and a first-time fit.

Heated sensor. Built for fast, consistent air/fuel ratio readings.

Specific fit. Made for a direct, no-guess installation.

Cross-references ACDelco 213-3905, Bosch 15928 and Delphi ES10942 for the same application. See all 8.

$214.02Free 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.

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Verify this part fits before purchasing — free returns if it doesn't
Step 2 — Quantity
Order total $214.02
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

Denso OE Style Air/Fuel Ratio Sensor

Denso 234-9121 is a heated air/fuel ratio sensor built for precise replacement and first-time fit. It is made to OE standards for the 2004-2006 Subaru Baja upstream position, giving you a direct-fit solution for air-fuel monitoring on the Subaru Baja.

The OE Style line focuses on exact replacement fitment and consistent sensor performance. For buyers searching for a Subaru Baja upstream air/fuel ratio sensor or a Denso 234-9121 replacement, this part is built to match the original application closely.

Key Features

  • Heated air/fuel ratio sensor for faster operating readiness
  • Specific fit for direct replacement on the listed application
  • 4-wire design
  • 37.80 in. wiring harness length
  • Regular grade type
  • OE Style replacement from Denso

Application Details

Compatible with 2004-2006 Subaru Baja, upstream. This Denso 234-9121 sensor is intended for the upstream location on the Subaru Baja and is a direct-fit option for drivers replacing a worn or faulty air/fuel ratio sensor.

This part cross-references Subaru (e.g., 22641AA260) for the same application.

What It Helps Address

  • Check engine light related to air/fuel ratio sensor performance
  • Rough idle caused by inaccurate exhaust feedback
  • Fuel trim issues from a degraded upstream sensor
  • Reduced engine efficiency from slow sensor response
  • Emissions test failures tied to sensor faults

Installation Notes

Verify the upstream sensor location before ordering and compare the connector, wire count, and harness length to the original part. On Subaru Baja applications, confirm the sensor routing and mounting point match the factory setup before installation. Use the vehicle’s service information for proper removal and torque procedures.

Quality Assurance

Denso manufactures and tests this OE Style sensor to strict original-equipment standards. The precision-built design supports accurate replacement fitment for the 2004-2006 Subaru Baja and helps ensure the right part for the right application the first time.

Related reading

This part fits 3 vehicles
Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.
YearMakeModelPositionNotes
2006SubaruBajaUpstreamOE Style
2005SubaruBajaUpstreamOE Style
2004SubaruBajaUpstreamOE Style
Directly replaces or cross-references 8 part numbers
Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.
ACDelco — 213-3905Bosch — 15928Delphi — ES10942NTK — 24695Standard Ignition — SG1858Subaru — 22641AA260Walker Products — 250-54025Walker Products — 350-64004