Delphi ES20394 Oxygen Sensor - Rear Left

Delphi ES20394 Oxygen Sensor for Rear Left Applications

The Delphi ES20394 is a heated oxygen sensor built for rear left placement on select 2001 Infiniti QX4 and 2001 Nissan Pathfinder models. It uses a 4-wire design, square connector shape, and 18 x 1.5 mm thread size for a direct-fit style replacement in emission control service.

Backed by Delphi’s OE heritage and decades of supplier experience with major automakers, this oxygen sensor reflects the engineering knowledge used in original equipment development. The ES20394 is supplied with an instruction sheet and is built for the rear left sensor position on the listed vehicles.

Key Features

• Heated oxygen sensor for emission control service
• 4-wire configuration for the listed application
• Square connector shape
• 18 x 1.5 mm thread size
• Overall length: 1240.0
• Position: rear left
• Package contents: oxygen sensor and instruction sheet

Detailed Description

Delphi ES20394 is an OE-style oxygen sensor engineered for rear left installation on 2001 Infiniti QX4 and 2001 Nissan Pathfinder models. The heated sensor design helps support exhaust monitoring after the catalytic converter, while the square connector and 4-wire layout match the listed fitment requirements. This part cross-references Bosch 15445 and DENSO Auto Parts 234-4327 for the same application.

For buyers searching for a 2001 Infiniti QX4 rear left oxygen sensor or a 2001 Nissan Pathfinder rear left oxygen sensor, ES20394 provides a direct reference point for emission control replacement. The thread size, connector style, and overall length are important details when matching the sensor to the vehicle’s exhaust system.

Common Issues This Part May Address

• Check engine light related to oxygen sensor performance
• Incorrect exhaust oxygen readings from a worn rear sensor
• Emission control faults tied to rear left sensor failure
• Rough fuel trim behavior caused by inaccurate sensor feedback
• Failed inspection results linked to sensor-related emissions codes

Installation Notes and Tips

Confirm rear left placement before installation and verify connector shape, wire count, and thread size against the removed sensor. On 2001 Infiniti QX4 and 2001 Nissan Pathfinder applications, note the fitment restrictions: Infiniti QX4 except mid year emissions, and Nissan Pathfinder to 08/2000. Use the vehicle’s service information to confirm the exact build date and emissions configuration before ordering or installing Delphi ES20394.

Quality Assurance

Delphi draws on more than 100 years of OE experience and supplier knowledge from original equipment development. That background is built into the ES20394 oxygen sensor for the listed rear left applications.