Bosch 15578 Oxygen Sensor - Upstream, Upstream Rear or Upstream Right

Bosch Validated Oxygen Sensor 15578

Bosch Validated Oxygen Sensor 15578 is a narrow-band heated O2 sensor built for precise air-fuel-ratio feedback to the ECU. It supports stable combustion control and emissions management in applications such as Mitsubishi Endeavor and Mitsubishi Eclipse.

Key Features

• Specific-fit Bosch oxygen sensor with a threaded mounting design
• Narrow-band heated sensor for faster closed-loop response
• 4-wire configuration with square male connector and blade terminals
• 25 in wiring harness length with included harness
• 18 mm thread size and 22 mm hex size
• Steel finish with metal housing for high-temperature service

Product Details

Part number 15578 uses Bosch switching-type oxygen sensor technology to measure exhaust oxygen content and send accurate feedback to the engine control unit. Bosch Validated Oxygen Sensor 15578 reflects Bosch’s long OE development history, including narrowband designs that improve light-off speed and lambda accuracy for quicker closed-loop operation. This makes it a direct replacement choice for vehicles that rely on precise upstream sensor input, including Mitsubishi Endeavor and Mitsubishi Eclipse applications.

This part cross-references Mitsubishi OE numbers MD335041 and MR985164 for the same application.

Common Issues It May Address

• Check engine light related to oxygen sensor performance
• Rich or lean fuel mixture readings from the upstream sensor
• Delayed closed-loop fuel control after startup
• Reduced emissions performance from a worn narrow-band sensor
• Unstable idle or drivability concerns tied to inaccurate air-fuel feedback

Installation Notes and Tips

Fits 2011 Mitsubishi Endeavor, Upstream Right. Fits 2010 Mitsubishi Endeavor, Upstream Rear. Fits 2004-2008 Mitsubishi Endeavor, Upstream Rear. Fits 1998-1999 Mitsubishi Eclipse, Upstream, with California Emission System. Confirm connector shape, thread size, and sensor position before installation. Use the correct oxygen sensor socket for the 22 mm hex and verify the harness routing matches the original layout.

Quality Assurance

Bosch backs this oxygen sensor with OE-driven engineering and durable materials selected for heat and vibration resistance. Part number 15578 is built to deliver consistent sensor output across demanding operating conditions.