Use a multimeter to detect the signal voltage of the automotive intake pressure sensor:
1) Remove the vacuum hose connecting the intake pressure sensor to the intake manifold.
2) Turn on the ignition switch (but do not start the engine).
3) Use a voltmeter to measure the output voltage of the intake manifold pressure sensor at the harness plug of the control unit (between the signal terminal PIM and the lap wire E1), then apply vacuum to the intake manifold pressure sensor, and measure the output voltage under different vacuum degrees. The voltage value should increase with the increase of the vacuum degree, and its change should comply with the provisions. If the difference is large, the intake pressure sensor may be damaged.
The intake pressure sensor is connected with the pressure stabilizing box to convert the pressure in the intake pipe into an electrical signal, which is transmitted to the ECU together with the speed signal as the basis for determining the basic injection amount of the injector.