I have an OBD2 hud display. It consists of the obd2 cable, and the device itself. Cable can disconnect from the device.

If I leave the cable plugged in, but the device is disconnected from it, does it still drain battery? The cable itself?

In other words, an open circuit. A cable that connects to OBD2 port, but the other end is not connected to anything (left hanging). Does it draw power?

1 Answer 1


The power supply for obd2 socket is a direct fused line to the battery. If the device attached has electronics in it, it will be consuming some power but it would likely be very very small in its idle state. If its just a cable to extend the obd2 power to the actual device that is unhooked then no it wont consume any additional power. It would be the same as if it was just the obd2 connector there.

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