Bosch 15742 Oxygen Sensor - Downstream or Upstream

Bosch OE Quality Oxygen Sensor 15742

Bosch 15742 is a specific-fit wideband oxygen sensor built for downstream applications on a wide range of GM vehicles. It delivers continuous air-fuel ratio feedback to the ECU, helping maintain accurate mixture control in everyday driving and under changing load conditions.

Key Features

• Wide-band sensor design for high-precision air-fuel ratio measurement across the lambda range
• Heated sensor with optimized heater control for faster operating readiness
• Specific-fit design with 4-wire harness, blade terminals, and oblong connector
• Threaded mounting with 18 mm thread diameter and 22 mm hex size
• Metal housing and ceramic construction for durability in thermal cycling
• Wiring harness included with a 12.5 in harness length and 15.9 in overall length
• Downstream fitment for Chevrolet, GMC, Buick, and Cadillac applications

Product Details

Bosch OE Quality Oxygen Sensor 15742 uses Bosch wideband A/F technology to provide the ECU with detailed exhaust feedback, rather than the limited switching signal of a conventional sensor. Bosch pioneered the planar pump-cell wideband design used in modern engine management, and this part reflects that OE development with fast light-off, stable heater control, and reliable signal response. It is a direct replacement for downstream service on vehicles such as the Chevrolet Camaro, Chevrolet Malibu, GMC Acadia, and Cadillac Escalade, and it also serves many other GM platforms listed in the fitment data. This part cross-references ACDelco 12657188 and 12661898 for the same application. Part number 15742 is built for drivers and technicians who need accurate emissions feedback and consistent drivability from a Bosch OE Quality Oxygen Sensor.

Common Problems This Sensor Can Help Address

• Check engine light related to oxygen sensor performance
• Incorrect air-fuel ratio readings from a worn downstream sensor
• Reduced fuel economy caused by inaccurate exhaust feedback
• Rougher engine operation after sensor aging or thermal damage
• Emissions test failures tied to faulty oxygen sensor output

Installation Notes and Tips

Verify the connector shape, 4-wire configuration, and threaded mounting style before installation. Bosch 15742 is a specific-fit sensor for downstream locations, so confirm the vehicle year, make, model, and position against the fitment list before ordering. Use the correct 18 mm oxygen sensor socket and inspect the exhaust bung threads before tightening the sensor to specification. On vehicles such as the Chevrolet Silverado 1500, GMC Sierra 1500, and Chevrolet Equinox, confirm the downstream location matches the original sensor placement.

Quality Assurance

Bosch has more than five decades of OE development in oxygen sensor technology and supplies aftermarket sensors built to OE-proven standards. The wideband design, heated operation, and robust construction support consistent performance in demanding exhaust environments.