Do you like to look at your AP gauges while driving but forgot to disconnect it after a drive, and your battery drained after a few days? Are you worried that repeatedly connecting and disconnecting your AP after driving may break the port? Or are you lazy like me and want to automate “true power off” for AP or other ODB2 port-based accessories? I have a solution for you!
The issue with the ODB2 port is that it only has one pin (#16) for power and it’s always on. When you turn the car off, AP says it’s turning off but recommends that you disconnect it to avoid draining the battery. It’s because AP goes into a deep sleep mode (and consumes a small amount of power) rather than truly powering off, so it can wake itself up when the car turns back on. I’ve also seen cases there the AP doesn’t even go into the sleep mode and stays on.
I decided to replace the always on 12V source with a switched source. In order to make it easily reversible, I bought a cheap
OBD2 16pins Male 1 to 2 Female Splitter on Amazon for $11. I cut the wires going to pin #16 on the male end and connected them to a fused switched 12V source for both female ports. Another option is to just cut one of the wires if you want the other port to have constant power.
I ran the initial test with an old OBDLink MX Bluetooth adaptor to avoid frying a much more expensive AP. Before, it turns on as soon as I plug it in and remains on until I unplug it (or the battery dies). With the new set up, it stays off until I turn the car on, and turns off when I turn the car off. This allows me to leave it plugged in for Torque Pro or FORScan without worrying about it draining the battery. AP behaves the same way as it turns off instantly when I turn the car off, as if I disconnected it manually.
One warning is that I’d not use the switched 12V source when flashing a new tune. In that case, just unplug the splitter and plug the AP in the original port, or use the constant power port if you only modified one port.
While the price was cheap, the splitter seems to be well made enough. The pins are numbered, which made double checking easier.
Cut the power wire for both female ports.
OBDLink MX stayed off when plugged in with the car off.
It powered on as soon as I turned the car on.