Как проверить блок управления ТНВД VP-44. Audi A6C5 2.5 TDI

How to make sure that the VP-44 injection pump control unit is working? This is especially important if for some reason the engine does not start. The reasons can be a huge number. Therefore, before changing the high-pressure fuel pump, you need to make sure that the high-pressure fuel pump control unit is operational, at least the voltage is supplied to the metering valve. To do this, you need an LED indicator - any 12-volt LED. We solder it to the probes and connect to the wires in parallel with the dispenser valve. When the starter scrolls, the LED should blink. Then we change the polarity of the probes and check again. If the LED blinks in different polarities, then the injection pump control unit is operational. If it blinks in one polarity and does not blink in the other, as a rule the matter is a transistor inside the high-pressure pump.