Engine Temperature Sensor

This sensor is critical for informing the Engine Control Unit (ECU) about the engine's thermal state, which in turn controls essential functions such as the air-fuel mixture, ignition timing, and the operation of the cooling fans. It features a distinctive green connector, a 4-pin configuration, and a 20mm clip, often used as an updated replacement for older black sensor styles. This sensor is specifically designed to replace the original part on a wide range of Audi A4 models from 1996 through 2004, including various engine and transmission configurations such as the 1.8L L4 and 2.8L V6 engines, in both automatic and manual transmissions, and FWD sedans and wagons. Specific fitments include: - 1996 Audi A4 with 2.8L V6 AFC Gas engine (Automatic/Manual FWD Sedan) - 1997-1999 Audi A4 with 1.8L L4 AEB/AWM Gas or 2.8L V6 AFC/AHA Gas engines (Automatic/Manual FWD Sedan) - 1998 Audi A4 Avant with 2.8L V6 AHA Gas engine (Automatic/Manual FWD Wagon) - 2000-2003 Audi A4 with 1.8L L4 ATW/AMB Gas or 2.8L V6 ATQ/AVK Gas engines (Automatic/Manual FWD Sedan, including CVT options) - 2003 Audi A4 Cabriolet with 1.8L L4 AMB Gas or 3.0L V6 AVK Gas engines (Automatic CVT FWD Convertible) - 2004 Audi A4 with 1.8L engine (Automatic FWD Sedan). A faulty coolant temperature sensor can lead to incorrect readings, causing issues like rough idling, poor fuel economy, black exhaust smoke, premature cooling fan activation, or even the vehicle entering "limp mode." It is also recommended to replace the O-Ring (N90316802) and C-Clip (032121142) when installing this sensor.