NTK 25041 Oxygen Sensor - Upstream, Upstream Left or Upstream Right

NTK Direct Fit Oxygen Sensor 25041

NTK 25041 is a direct fit heated oxygen sensor built for specific applications and OE-style replacement needs. It is engineered with a 4-wire configuration, threaded mounting, and a 20-inch wiring harness for a precise replacement on select BMW models.

As part of NTK’s Direct Fit Oxygen Sensor line, this sensor reflects the brand’s focus on application-specific coverage, ceramic sensor manufacturing expertise, and OE-level fit, form, and function. For drivers searching for a BMW 318i oxygen sensor, BMW 325i upstream oxygen sensor, or NTK 25041 replacement, this part is built to match the original sensor layout.

Key Features

• Heated oxygen sensor for faster operating response
• Specific fit design for direct replacement
• 4-wire configuration
• 18 mm thread diameter with threaded mounting
• 20-inch wiring harness length
• OE-style replacement for upstream sensor locations
• Cross-reference example: Bosch 13231

Fitment Details

• Fits 1992-1995 BMW 318i, upstream.
• Fits 1993-1995 BMW 318is, upstream.
• Fits 1995 BMW 318ti, upstream.
• Fits 1992-1995 BMW 325i, upstream.
• Fits 1992-1995 BMW 325is, upstream.
• Fits 1994-1995 BMW M3, upstream.
• Fits 1994 BMW 530i, upstream right.
• Fits 1994 BMW 530i, upstream left.
• Fits 1994 BMW 540i, upstream right.
• Fits 1994 BMW 540i, upstream left.
• Fits 1994 BMW 840Ci, upstream right.
• Fits 1994 BMW 840Ci, upstream left.
• Fits 1992 BMW 318is, upstream.

What This Sensor Helps Address

• Check engine light related to oxygen sensor performance
• Incorrect air-fuel ratio readings at the upstream sensor
• Slow sensor response during closed-loop operation
• Rough idle or drivability issues tied to sensor signal quality
• Failed emissions inspection caused by a worn oxygen sensor

Installation Notes

Confirm the vehicle’s sensor position before ordering, since this part is listed for upstream locations including Bank 1 Sensor 1 and select Bank 2 Sensor 1 applications. Verify connector style, harness length, thread diameter, and wire count against the original sensor on the BMW 318i, 325i, and M3 applications listed here.

Use the vehicle’s build date and engine configuration when checking 1994 BMW 530i, 540i, and 840Ci fitment, as the listing includes date-specific upstream left and upstream right applications. For best results, compare the original sensor routing and mounting style before installation.

Quality Assurance

NTK is a major original equipment oxygen sensor manufacturer with extensive manufacturing and testing controls. The sensor is produced with ceramic technology developed in-house and is tested during production to meet or exceed OE specifications for fit and reliability.