Identification and Detection of Semiconductor Varistor-type Intake Air Pressure Sensor 2

Figure 2 Working Principle of the Varistor-type Intake Manifold Pressure Sensor diode

Since one side of the silicon diaphragm is a vacuum chamber, the higher the intake manifold pressure, the greater the deformation of the diaphragm, and its strain is directly proportional to the pressure. The resistance of the strain resistor attached to the film changes proportionally with the pressure, allowing the deformation of the silicon diaphragm to be converted into an electrical signal using a Wheatstone bridge. Due to the weak output electrical signal, a hybrid integrated circuit is used for amplification before output. diode

(2) Testing the Intake Manifold Pressure Sensor of General Motors

A malfunction in the intake manifold pressure sensor or its wiring can cause issues such as poor idle, difficulty starting, or stalling after startup. When a fault is diagnosed, the manifold pressure sensor and its connected circuit should be promptly inspected.diode

The connection circuit between the intake manifold pressure sensor and the ECU is shown in Figure 3. As seen in the figure, it has three wiring connections: one for the Vcc power line, one for the PIM signal output line, and another for the ground. The output signal voltage of this sensor should be checked. At idle, it is 0.9V. As the engine speed increases, the vacuum level decreases, and the output voltage rises, with a maximum not exceeding 5V. diode