NTK 24345 Air / Fuel Ratio Sensor - Upstream or Upstream Left

NTK Direct Fit Air/Fuel Ratio Sensor 24345

NTK 24345 is a direct fit, heated 5-wire air/fuel ratio sensor built for specific BMW and Mercedes-Benz applications. It is engineered for OE-equivalent fit, form, and function, with a 47.3 in. wiring harness and an 18.0 mm thread diameter for the listed upstream positions.

Key Features

• Direct fit 5-wire air/fuel ratio sensor for specific applications
• Heated sensor design for faster operating response
• 47.3 in. wiring harness length
• 18.0 mm thread diameter with 0.38 in. thread length
• Specific fit design for OE-style replacement
• No mounting bracket included

Product Line Details

NTK Direct Fit sensors are part of NTK’s OE-focused sensor line, developed under the NGK family of products. The brand uses controlled ceramic manufacturing and extensive testing to deliver consistent sensor performance and application coverage for import and domestic vehicles.

Detailed Description

This NTK air/fuel ratio sensor is designed for upstream use on select BMW 335i, 535i, X6, Z4, 135i, 335is, 1 Series M, and related applications, as well as select Mercedes-Benz E320 and CLK63 AMG listings. It is a specific-fit replacement for vehicles requiring a 5-wire heated A/F sensor, and it cross-references Bosch 17102 and DENSO Auto Parts 234-5027 for the same application. Part number 24345 is built to match OE-equivalent design requirements for direct replacement service.

Vehicle Fitment

• Fits 2009-2016 BMW Z4, Upstream; Cyls. 4-6; B2S1; OE Equivalent Design; Direct Fit 5-Wire A/F Sensor
• Fits 2011-2013 BMW 335is, Upstream; Cyls. 4-6; B2S1; OE Equivalent Design; Direct Fit 5-Wire A/F Sensor
• Fits 2011 BMW 1 Series M, Upstream; Cyls. 4-6; B2S1; OE Equivalent Design; Direct Fit 5-Wire A/F Sensor
• Fits 2008-2010 BMW 135i, Upstream; Cyls. 4-6; B2S1; OE Equivalent Design; Direct Fit 5-Wire A/F Sensor
• Fits 2007-2010 BMW 335i, Upstream; Cyls. 4-6; B2S1; OE Equivalent Design; Direct Fit 5-Wire A/F Sensor
• Fits 2009-2010 BMW 335i xDrive, Upstream; Cyls. 4-6; B2S1; OE Equivalent Design; Direct Fit 5-Wire A/F Sensor
• Fits 2008-2010 BMW 535i, Upstream; Cyls. 4-6; B2S1; OE Equivalent Design; Direct Fit 5-Wire A/F Sensor
• Fits 2009-2010 BMW 535i xDrive, Upstream; Cyls. 4-6; B2S1; OE Equivalent Design; Direct Fit 5-Wire A/F Sensor
• Fits 2008-2010 BMW X6, Upstream; Cyls. 4-6; B2S1; OE Equivalent Design; Direct Fit 5-Wire A/F Sensor
• Fits 2007-2009 Mercedes-Benz CLK63 AMG, Upstream Left; Compatible with downstream oxygen sensor designed to meet OE specifications.; Direct Fit 5-Wire A/F Sensor
• Fits 2007-2008 BMW 335xi, Upstream; Cyls. 4-6; B2S1; OE Equivalent Design; Direct Fit 5-Wire A/F Sensor
• Fits 2008 BMW 535xi, Upstream; Cyls. 4-6; B2S1; OE Equivalent Design; Direct Fit 5-Wire A/F Sensor
• Fits 2005-2006 Mercedes-Benz E320, Upstream; B1S1; Equipped w/ 1 Upstream Sensor Only; OE Equivalent Design; Direct Fit 5-Wire A/F Sensor

Common Issues This Sensor Can Address

• Fault codes related to air/fuel ratio sensor response or heater circuit performance
• Rough idle or inconsistent fuel control caused by a failing upstream sensor
• Reduced drivability from inaccurate exhaust oxygen feedback
• Emissions test failures tied to sensor degradation
• Replacement needs after sensor wiring or element wear

Installation Notes

Confirm the connector style, wire count, and upstream position before installation. This sensor uses a specific-fit design with a 5-wire heated configuration, so verify the vehicle’s original sensor layout and thread size match the listed specifications. No mounting bracket is included.

Quality Assurance

NTK manufactures oxygen and air/fuel ratio sensors with OE-focused engineering and extensive production testing to help ensure quality and reliability that meet or exceed OE specifications. Part number 24345 is built for direct-fit service on the listed BMW and Mercedes-Benz applications.