Bosch 15897 Oxygen Sensor - Downstream

Bosch Oxygen Sensor for Downstream Control

Bosch Part Number 15897 is a specific-fit, narrow-band heated oxygen sensor for downstream applications. It monitors exhaust oxygen content and sends precise air-fuel-ratio data to the ECU, helping maintain stable combustion control and lower emissions.

Key Features

• Bosch Engineered Oxygen Sensor line built on decades of OE development
• Narrow-band heated O2 sensor for downstream placement
• 4-wire design with square connector, male connector gender, and female terminals
• Threaded mounting with 18 mm thread diameter and 22 mm hex size
• Wiring harness included with 27 in harness length and 30.7 in overall length
• Metal housing and high-temperature-resistant construction for demanding exhaust conditions
• Cross-references OE numbers 12578576 and 21024460 for the same application

Product Details

Bosch 15897 is part of the Bosch Engineered Oxygen Sensor product line, which focuses on OE-style sensor performance for emission control systems. This narrow-band heated oxygen sensor uses advanced ceramic elements and optimized heater control to support faster closed-loop operation and accurate lambda feedback after warm-up. It is a direct replacement for downstream service on select Chevrolet, Pontiac, and Saturn vehicles, including Chevrolet HHR, Chevrolet Cobalt, Pontiac G5, and Saturn Ion applications.

Fits 2006-2011 Chevrolet HHR, Downstream. Fits 2005-2010 Chevrolet Cobalt, Downstream. Fits 2007-2010 Pontiac G5, Downstream. Fits 2005-2007 Saturn Ion, Downstream. Fits 2002-2007 Saturn Vue, Downstream. Fits 2005-2006 Pontiac Pursuit, Downstream. Fits 2004 Saturn L300, Downstream. Fits 2002-2003 Saturn L200, Downstream. Fits 2002-2003 Saturn LW200, Downstream. Fits 2002 Saturn L100, Downstream. Fits 2000-2002 Saturn SC1, Downstream. Fits 2000-2002 Saturn SC2, Downstream. Fits 2000-2002 Saturn SL, Downstream. Fits 2000-2002 Saturn SL1, Downstream. Fits 2000-2002 Saturn SL2, Downstream. Fits 2000-2001 Saturn SW2, Downstream.

What It Helps Address

• Faulty downstream oxygen sensor readings
• Check engine light concerns related to O2 sensor performance
• Rich or lean fuel control issues caused by inaccurate exhaust feedback
• Emissions test failures tied to sensor response problems
• Slow closed-loop transition after engine warm-up

Installation Notes and Tips

Verify the connector shape, wire count, thread size, and downstream location before installation. This Bosch 15897 sensor uses a threaded mount and a specific-fit harness, so matching the original connector and routing is important for proper installation on Chevrolet HHR, Chevrolet Cobalt, Pontiac G5, and Saturn applications. Inspect the exhaust bung threads and wiring path before tightening the sensor.

Quality Assurance

Bosch has more than five decades of OE oxygen sensor development behind this design. The sensor uses durable materials, heater control, and ceramic sensing elements selected for consistent operation under heat and vibration in everyday emission control service.