What is the reason for the fault light of BMW 5 engine

The reasons for the check engine light on BMW's 5 Series models are: sensor problems, poor combustion of the mixture, maintenance problems and oil quality problems. Poor combustion of the mixture: engine spark plug failure, fuel pump failure, ignition coil failure, oil circuit blockage, etc. will lead to poor combustion of the engine mixture.

　　

Specifically divided into: 1. Poor combustion of the mixture: engine spark plug failure, fuel pump failure, ignition coil failure, oil circuit blockage, etc. will all lead to poor combustion of the engine mixture. The bad combustion of the mixture can cause the problem of carbon deposits or knocking in the engine, which is detected by the oxygen sensor of the engine, and the fault light will come on after being transmitted to the ECU as a warning. 2. Sensor problem: intake air temperature, crankshaft position, including water temperature, air flow, oxygen sensor, etc. When these sensors are damaged, poorly connected or the signal is interrupted, the ECU of the car cannot accurately obtain the engine data, causing the engine fault light to turn on. 3. Maintenance issues: Poor engine maintenance is the most common cause of engine failure lights. 4. Engine oil quality issues: The fuel filled in cars is usually marked, and engine oil is also divided into semi-synthetic and fully synthetic. Manufacturers usually advise car owners which brand of fuel and which type of engine oil to use. If the owner does not add it as required, it will cause engine wear for a long time and cause the fault light to light up.