How to check and repair vehicle sensors?

How to check and repair vehicle sensors?

Air flow sensor

The air flow sensor converts the inhaled air into an electrical signal and sends it to the electronic control unit (ECU) as one of the basic signals for determining fuel injection. According to the different measuring principles, it can be divided into four types: rotary vane air flow sensor (Toyota Previa station wagon), Carmen vortex air flow sensor (Toyota Lexus LS400 car), hot wire air flow sensor (VG30E engine for Nissan Maxima, TJ648 1AQ4 engine for Volvo B230F for domestic Tianjin Sanfeng bus) and hot film air flow sensor. The first two are volume flow type and the last two are mass flow type. At present, hot-wire air flow sensor and hot-film air flow sensor are mainly used.

Intake pressure sensor

The intake pressure sensor can measure the absolute pressure in the intake manifold according to the load state of the engine, and convert it into an electrical signal, which is sent to the computer together with the speed signal as the basis for determining the basic fuel injection quantity of the injector. This kind of pressure sensor is used in domestic Audi 100 car (V6 engine), Santana 2000 car, Beijing Cherokee (25L engine) and Toyota Crown 3.0 car. Semiconductor piezoresistive intake pressure sensor is widely used.

Throttle position sensor

The throttle position sensor is installed on the throttle to detect the opening of the throttle. It is linked with the throttle through the lever mechanism, and then reflects the different working conditions of the engine. This sensor can detect different working conditions of the engine, and then input it into ECU to control different fuel injection quantity. There are three types of throttle position sensors (Santana 2000 and Tianjin Sanfeng Bus), linear variable resistance throttle position sensor (Beijing Cherokee) and comprehensive throttle position sensor (domestic Audi 100 V6 engine).

Crankshaft position sensor

Crankshaft angle sensor, also known as crank angle sensor, is the most important sensor in computer-controlled ignition system. Its function is to detect the top dead center signal, crank angle signal and engine speed signal, and input them into the computer, so that the computer can issue the best ignition time instruction according to the ignition sequence of cylinders. There are three kinds of crankshaft position sensors: electromagnetic pulse crankshaft position sensor, Hall effect crankshaft position sensor (Santana 2000 and Beijing Cherokee) and photoelectric effect crankshaft position sensor. Different types of crankshaft position sensors have different control modes and control accuracy. Crankshaft position sensors are generally installed on one side of crankshaft pulley or sprocket, some are installed at the front end of camshaft, and some are installed on distributor (Santana 2000).

Knock sensor

The knock sensor is installed on the cylinder block of the engine to monitor the knock of the engine at any time. * * * mode and non-* * mode are used!