If a Bluetooth OBDII is plugged in does it draw power when the engine is off. Mercedes, ML-320, 2002

Question

I want to leave the bluetooth OBD-II plugged in always. one friend said it may drain the car battery. I want to know if it is true.

Answer 1

On the OBD link connector pin 16 is battery voltage, It is also fuse protected, even with the key taken out and engine off there is power, so the OBD II will stay on. It may not be able to drain a good battery, but it will drain the battery.