Bosch 13613 Oxygen Sensor - Upstream

Bosch Wideband Oxygen Sensor for Toyota

Bosch Validated Oxygen Sensor 13613 is a specific-fit wideband A/F oxygen sensor for select Toyota applications. It delivers continuous air-fuel ratio feedback to the ECU, helping maintain precise mixture control in upstream locations on Toyota Tacoma, Tundra, and 4Runner models.

Key Features

• Wideband A/F oxygen sensor for accurate lambda measurement across the full operating range
• Heated design for faster sensor warm-up and stable operation
• Specific-fit replacement with a 4-wire harness and square male connector
• 18 mm thread diameter, 22 mm hex size, and flange mounting type
• Metal housing with robust ceramic sensor construction for demanding thermal cycles
• Wiring harness included with a 10-inch harness length and 12.2-inch sealing-surface-to-connector length

Product Details

Bosch 13613 is part of the Bosch Validated Oxygen Sensor line, built around Bosch wideband technology that measures air-fuel ratio continuously rather than only switching rich or lean. Bosch pioneered the planar pump-cell wideband design used in modern engine management, and this sensor reflects that OE development history with fast light-off, controlled heater performance, and durable construction. It is a direct-fit upstream oxygen sensor for 2001-2004 Toyota Tacoma, 2001-2004 Toyota Tundra, 2001-2002 Toyota 4Runner, and 1999-2000 Toyota 4Runner with California Emission System, plus 2000 Toyota Tacoma and 2000 Toyota Tundra with California Emission System. This part cross-references Toyota OE numbers 8946734021 and 8946735011 for the same application.

What This Sensor Helps Address

• Check engine light related to upstream air-fuel ratio sensor performance
• Incorrect fuel trim readings from a worn wideband sensor
• Rough idle or hesitation caused by inaccurate mixture feedback
• Reduced fuel economy from poor air-fuel control
• Elevated emissions from delayed or unstable sensor response

Installation Notes

Install Bosch 13613 in the upstream position only on the listed Toyota applications. Verify the connector shape, 4-terminal layout, 18 mm thread size, and harness routing before installation. Because this is a wideband sensor, avoid contaminating the sensing element during handling and confirm the exhaust threads and flange mounting surface are clean before tightening.

Quality Assurance

Bosch backs this oxygen sensor with more than five decades of OE development experience and validated aftermarket engineering. The Bosch Validated Oxygen Sensor line is built to OE-proven standards for accurate signal output, reliable heater control, and consistent performance in demanding engine-management systems.