Help: The tour guide has engine trouble and the light is always on.

The engine fault light of the car guide is always on, which is generally a sensor problem. Go to the repair shop and check it with a computer diagnostic instrument. But only maintenance and replacement, and finally troubleshooting.

Automobile sensor is the input device of automobile computer system, which converts various working condition information in automobile operation, such as vehicle speed, temperature of various media, engine working condition and so on. , converted into electrical signals and transmitted to the computer, so that the engine is in the best working condition. There are many sensors on the vehicle. When judging the fault of the sensor, not only the sensor itself, but also the whole faulty circuit should be considered. Therefore, when looking for faults, besides checking the sensor, we should also check the wiring harness, connectors and related circuits between the sensor and the electronic control unit.

At present, there is no unified classification method for sensors, but there are three commonly used methods:

1. According to the physical quantities of sensors, it can be divided into displacement, force, speed, temperature, flow, gas composition and other sensors.

2. According to the working principle of the sensor, it can be divided into resistance, capacitance, inductance, voltage, Hall, photoelectric, grating, thermocouple and other sensors.

3. According to the nature of the sensor output signal, it can be divided into: switch-type sensors whose outputs are switching values ("1" and "0" or "on" and "off"); The output is an analog sensor; Digital sensor whose output is pulse or code.