Bosch 18121 Oxygen Sensor - Upstream

Bosch Wideband O2 Sensor for Land Rover

Bosch Validated Oxygen Sensor 18121 is a specific-fit wideband air-fuel ratio sensor for select Land Rover applications. It delivers continuous, high-precision AFR feedback to the ECU, helping maintain accurate fuel control across changing load and temperature conditions.

Built with a heated design, 4-wire blade terminals, and a threaded 18 mm mounting style, this Bosch oxygen sensor is made for direct replacement service on upstream positions in the Land Rover LR4, Range Rover Sport, and Range Rover.

Key Features

• Wideband A/F oxygen sensor for precise lambda measurement
• Heated sensor with optimized heater control for faster response
• Specific-fit replacement with included wiring harness
• 4-wire configuration with rectangle male connector
• Threaded mounting, 18 mm thread diameter, 22 mm hex size
• Metal housing with standard replacement grade construction
• Bosch part number 18121 for OE-style service applications

Product Details

Bosch pioneered the wideband planar pump-cell sensor design used in modern engine management, and Bosch Validated Oxygen Sensor 18121 reflects that OE development background. This sensor provides detailed air-fuel ratio data rather than simple switching output, allowing the engine control system to manage mixture more accurately during acceleration, cruising, and thermal cycling. It is a direct-fit upstream sensor for 2010-2013 Land Rover LR4, 2010-2013 Land Rover Range Rover Sport, and 2010-2012 Land Rover Range Rover. This part cross-references LR011710 for the same application.

Common Issues It Can Help Address

• Fault codes related to upstream oxygen sensor performance
• Rough idle caused by inaccurate air-fuel ratio feedback
• Reduced fuel economy from poor mixture control
• Delayed sensor response during warm-up or load changes
• Emissions test failures tied to sensor degradation

Installation Notes and Tips

Install Bosch 18121 in the upstream position only where specified by the vehicle application. Confirm connector shape, wire count, thread size, and harness length before installation. Use proper oxygen sensor service tools and follow the vehicle manufacturer’s torque and routing specifications to avoid damage to the sensor or exhaust threads.

Quality Assurance

Bosch draws on more than five decades of OE sensor development, and this validated oxygen sensor is built to the same type of engineering standards used in modern engine management systems. For Land Rover LR4, Range Rover Sport, and Range Rover applications, Bosch 18121 is a direct replacement option backed by Bosch’s OE-focused sensor expertise.