We connect the tester probes to the terminals "A" and "C" of the block of the wiring harness.
With the ignition on, the voltage should be 4.5-5.5 V.
Similarly, we measure the voltage between the terminals "B" and "C".
The device should fix the voltage of 4.5-5.5 V.
If the voltage values do not correspond to the norm, we check the health of the circuits (open and short to ground) between terminal "A" of the wiring harness block and terminal "M48" of the computer harness block, between terminal "B" of the wiring harness block and terminal "M8" of the computer harness block, and also between terminal "C" of the wiring harness block and terminal "M16" of the block ECU harness.
If the voltage values \u200b\u200band serviceable circuits do not match, the computer is faulty.
To check the sensor, we connect the block of the wiring harness to it.
From the side of the input of the wires into the socket of the block corresponding to the output "B", we insert a piece of wire so that there is contact between it and the output.
With the ignition on and creating a vacuum (through the suction hose to the sensor) …
..measure the voltage between terminal "B" of the wiring harness block and "ground".
The readings of the device should vary from 4.5–5.5 V (Atmosphere pressure) up to 0.5–1.0 V (negative pressure 68 kPa).
You can roughly estimate the performance of the sensor by creating a vacuum in the hose with your mouth.
In this case, the voltmeter readings change from 4.5 V to 2.0 V.
Replace the defective sensor with a new one.