Standard Ignition TX121 Engine Coolant Temperature Sensor

Engine Coolant Temperature Sensor for Mercedes-Benz

Standard Ignition TX121 is an engine coolant temperature sensor built for direct replacement on select Mercedes-Benz applications. It uses a bolt-on attachment method with a round, plug-in female connector and 3 male pin terminals for a secure electrical connection.

For Mercedes-Benz 190E, 300D, 300E, 300SE, 300SEL, 300SL, 300TE, 300CE, 300SD, 560SEC, and 560SEL applications, this sensor supports accurate coolant temperature input to the engine management system. The TX121 part number is also a useful reference when matching the correct replacement sensor for these vehicles.

Key Features

• Engine coolant temperature sensor for select Mercedes-Benz models
• Bolt-on attachment method for direct mounting
• Round, plug-in female connector
• 3 male pin terminals for electrical connection
• Standard Ignition TX121 replacement part number
• Cross-reference part numbers include 0065454524 and SU7685

Detailed Description

Standard Ignition TX121 is an engine coolant temperature sensor designed for vehicles that rely on coolant temperature data for fuel and engine control decisions. The connector design, terminal layout, and bolt-on mounting style help match the original sensor configuration on supported Mercedes-Benz platforms. This part is listed for 1990-1993 Mercedes-Benz 300D, 1990-1991 Mercedes-Benz 300E, and 1991-1993 Mercedes-Benz 190E, along with additional 1990s Mercedes-Benz applications including 300SE, 300SEL, 300SL, 300TE, 300CE, 300SD, 560SEC, and 560SEL.

This part cross-references 0065454524 and SU7685 for the same application.

Common Replacement Reasons

• Incorrect coolant temperature readings
• Hard starting or poor cold-engine operation
• Rough idle related to temperature input errors
• Check engine light triggered by sensor signal faults
• Driveability issues caused by inconsistent engine temperature data

Installation Notes

Verify connector shape, terminal count, and mounting style before installation. Confirm the vehicle application by year and model, since fitment varies across Mercedes-Benz 190E, 300D, 300E, 300SE, 300SEL, 300SL, 300TE, 300CE, 300SD, 560SEC, and 560SEL configurations. One 1990 Mercedes-Benz 190E listing applies only to vehicles equipped with California emissions. The 1986-1989 Mercedes-Benz 560SEC listing is noted as a 3 terminal manifold absolute pressure sensor application, so confirm the exact sensor location and system requirements before ordering.

Quality Assurance

Standard Ignition replacement parts are built to match the specified connector and mounting requirements for the listed applications. TX121 is intended for direct-fit service on the confirmed Mercedes-Benz fitments shown above.