Quick question: Is the OBD2 port powered (live) when the car is off (prior to pressing START button, after shutting down with START button, systems not at READY)? Situation: On the 2012 v Five, I have a sensor attached to the OBD2 port whose LCD display of engine and systems parameters has recently decided to stay on, powered after the car has been shut down.
Powered up all the time. Some smart devices monitor the voltage level and sleep below 13v. That is not always reliable, so my P10 monitor also watches for rpm and will sleep after a period of minutes without rpm.
Memory saver cables (for maintaining 12 volt when swapping batteries) take advantage of the constant-on 12 volt in the OBD port, have just the 12 volt pins.
If I remember right, the ScanGauge II had a "hybrid mode" I could select during setup, so it would not go to sleep every time the engine stopped. But I set it up a long time ago, so I might not remember right.
It’s a P10 that is staying on. Just changed the 12V battery, whose resting voltage is below 13v. (Didn’t happen with the six year old end of life battery.)
There are several adjustments. I believe I set the off timer to 180 seconds, verified it did not have a speed offset and set it for one of the protocols as listed in step 10 in pdf.
I believe you had it right; it functions while the engine is stopped. However, my ScanGauge II shows phantom fuel consumption when the car is coasting with injectors and ignition off, so the fuel consumption-related data it shows is not credible. For the same reason, the fuel calibration procedure shown in the manual never settles on any one value as it should.
