Failure of Weipai VV7 air flowmeter

Faults of air flow sensors can be divided into two categories. One is that the signal exceeds the specified range, indicating that the air flow sensor is faulty. Modern electronically controlled vehicles have fail-safe function. When the signal of a sensor fails, the electronic control unit (ECU) will replace it with a fixed value, or replace the signal of the faulty sensor with the signal of other sensors. The other is inaccurate signal (i.e. performance drift). Inaccurate air flow sensor signal may be more harmful than no signal. This is because. Because the signal is not beyond the specified range. The electronic control unit (ECU) will control the fuel injection quantity according to this inaccurate air flow signal, so it will often cause the mixed steam to be too thin or too rich. If there is no air flow signal, ECU will use the signal of throttle position sensor instead, and the idle speed of the engine is relatively stable.