What is the part number of the oxygen sensor on a Subaru WRX?
There isn’t a single part number that fits all Subaru WRX models. The exact oxygen sensor part number varies by year, engine variant, sensor location (upstream vs downstream), and market. To be sure, identify your car’s specifics and look up the official catalog or trusted parts suppliers for the precise OE number.
Why the part number varies across WRX models
The WRX has undergone several powertrain changes across generations, and oxygen sensors are split by function and placement. The combination of engine type, year, and whether you’re replacing the pre-cat (upstream) or post-cat (downstream) sensor determines the exact part number.
- Engine code and model year
- Sensor location and designation (e.g., upstream vs downstream; Bank 1 vs Bank 2 on engines with multiple banks)
- Market or region (US, EU, Asia, etc.) and dealer catalog differences
- OEM vs aftermarket options and compatibility with heater circuits
Because of these variables, always verify with the official catalog or by inspecting the sensor’s connector and thread size on the vehicle.
How to identify the correct oxygen sensor part number for your WRX
Follow these steps to determine the exact OE part number for your vehicle, ensuring you order the right sensor the first time.
- Gather essential details: model year, engine code (for example, FA20 or EJ-series), and your vehicle VIN.
- Inspect the current sensor: look for a stamped or printed part number on the sensor body, or check the wiring harness label that accompanies the sensor.
- Use the official Subaru parts catalog or dealer portal: search by VIN or engine code for the entries labeled Bank 1 Sensor 1 (upstream) and Bank 1 Sensor 2 (downstream).
- Cross-check with reputable retailers and OEM suppliers: compare the listed OE numbers from SubaruParts, dealer catalogs, and the sensor manufacturer (Denso, Bosch, etc.) to confirm fitment, including thread size and heater version.
- If in doubt, contact a Subaru dealer with your VIN to confirm the exact OE part numbers for both sensors if needed.
OE vs aftermarket considerations
Original equipment sensors from Denso or Subaru are typically listed with the exact OE part numbers and warranty terms. Aftermarket sensors can vary in fit, performance, and warranty, so use caution and verify compatibility with your WRX’s year and engine configuration.
Having the exact numbers helps ensure correct fitment and proper sensor performance, reducing the risk of poor emissions readings or failed inspections.
Common pitfalls to avoid
Avoid assuming all WRX oxygen sensors are interchangeable or that a single part number covers every year and engine variant. Pay attention to sensor location, bank designation, and whether the car uses one or more catalytic converters requiring multiple sensors.
- Overlooking the difference between upstream (Bank 1 Sensor 1) and downstream (Bank 1 Sensor 2) sensors
- Replacing only one sensor when both are due for maintenance or replacement
- Buying an aftermarket sensor without verifying the exact OE compatibility for your VIN
Correctly identifying the sensor ensures proper engine management, emission compliance, and prolongs both sensor life and catalytic converter health.
Summary
For a Subaru WRX, there isn’t a universal oxygen sensor part number. The precise OE number depends on year, engine variant, and sensor placement. Start with your VIN, inspect the existing sensor for its part marking, and consult Subaru’s official parts catalog or a trusted dealer to confirm the exact upstream and downstream sensor numbers. When in doubt, rely on the dealer or OEM-specified parts to guarantee the correct fit and performance.
