Walker 250-241285 Oxygen Sensor - Downstream Rear

Walker OE Base Oxygen Sensor for Acura RLX

Walker 250-241285 is a heated narrow-band oxygen sensor built as a specific-fit OE Base Sensor for the downstream rear position. It is engineered for 2018-2020 Acura RLX applications and provides the ECU with the feedback needed for emissions and fuel-control monitoring.

The Walker OE Base Sensor line focuses on application-specific replacement parts for exact fitment and diagnostic response. For Acura RLX owners searching for a downstream rear oxygen sensor, 250-241285 is matched to the B1S2 location and uses a 4-wire, oblong female connector with M18 x 1.5 threads.

Key Features

• Specific-fit oxygen sensor for the downstream rear position
• Heated narrow-band design for faster operating response
• 4-wire configuration with 4 terminals
• Oblong connector shape with female connector gender
• Male spade terminals
• 22 mm wrench size
• M18 x 1.5 thread size
• Walker OE Base Sensor line for application-matched replacement

Detailed Description

Walker 250-241285 is an emission control oxygen sensor intended for 2018, 2019, and 2020 Acura RLX models in the downstream rear position. This sensor is identified for B1S2 service and is built to deliver the signal the ECU expects from the affected exhaust location. If you are replacing an Acura RLX downstream rear oxygen sensor, this part number provides the correct fitment details for that application.

As part of Walker Products’ OE Base Sensor line, this oxygen sensor is developed around vehicle-specific fitment rather than universal coverage. That approach helps ensure the connector style, terminal layout, thread size, and sensor type align with the original application. Walker 250-241285 is a practical choice when servicing emissions-related faults on the Acura RLX.

What It Can Help Address

• Check engine light related to the downstream rear oxygen sensor
• Fault codes stored in the ECU for B1S2 sensor performance
• Poor fuel economy caused by inaccurate exhaust feedback
• Elevated exhaust emissions from a failing oxygen sensor
• Rough engine operation tied to sensor signal issues

Installation Notes and Tips

Before replacement, inspect the sensor wiring harness and connector for heat damage, corrosion, or broken terminals. Confirm the downstream rear location and B1S2 application on the vehicle before installation. Use the correct 22 mm wrench size and verify the M18 x 1.5 thread engagement during service. For Acura RLX oxygen sensor replacement, matching the connector shape and terminal layout is important for proper installation.

Quality Assurance

Walker Products has manufactured engine management and oxygen/air-fuel sensors since 1946 and operates as an ISO 9001/TS 16949 certified company. The OE Base Sensor line is built around application-specific replacement requirements for accurate fitment and diagnostic feedback. Part number 250-241285 reflects that OE-style approach for the 2018-2020 Acura RLX downstream rear oxygen sensor application.