NTK 21043 Oxygen Sensor - Downstream

Direct Fit Downstream Oxygen Sensor

NTK Direct Fit Oxygen Sensor 21043 is a heated, specific-fit replacement built for downstream monitoring on select Chevrolet, Pontiac, and Saturn applications. It uses a 4-wire design with a threaded mounting style and an 18 mm thread diameter for OE-style service on the vehicles listed below.

Key Features

• Heated oxygen sensor for downstream exhaust monitoring
• Specific-fit design for direct replacement installation
• 4-wire configuration with 27.75 in. wiring harness length
• Threaded mounting with 18 mm thread diameter
• Built to meet or exceed OE specifications during manufacturing testing
• NTK part number 21043 for catalog and service reference

Product Details

NTK is a major original equipment oxygen sensor manufacturer, and the 21043 reflects that OE-focused approach with fit, form, and function aligned to factory requirements. As part of the Direct Fit Oxygen Sensor line, this sensor is intended for downstream positions and is listed for 2006-2011 Chevrolet HHR, 2005-2010 Chevrolet Cobalt, 2007-2010 Pontiac G5, and select Saturn applications including Ion, Vue, L300, L200, LW200, L100, SC1, SC2, SL, SL1, SL2, and SW2. If you are replacing a downstream oxygen sensor on a Chevrolet Cobalt or Saturn Vue, NTK 21043 provides a direct replacement path without universal-fit adaptation.

This part cross-references Bosch 15897 and DENSO Auto Parts 234-4066 for the same application.

What It Helps Address

• Check engine light concerns related to downstream oxygen sensor performance
• Incorrect exhaust oxygen readings after sensor aging or contamination
• Emissions system faults tied to the B1S2 downstream sensor location
• Rough fuel control feedback caused by a failing heated oxygen sensor
• Service replacement needs on Chevrolet HHR, Chevrolet Cobalt, Pontiac G5, and Saturn models

Installation Notes

Verify the downstream sensor location and connector match before installation. The threaded mounting design and specific-fit harness are intended to align with the listed vehicle applications, including 2006-2011 Chevrolet HHR, 2005-2010 Chevrolet Cobalt, and 2007-2010 Pontiac G5. Confirm thread diameter, wire count, and harness length against the original sensor before service.

Quality Assurance

NTK states that its oxygen sensors are extensively tested during manufacturing to meet or exceed OE specifications. The brand also notes its role as a major supplier of original equipment oxygen sensors, with ceramic technology and OE application support built into the product line.