Connection not restoring after car shutdown

Hi @realdashdev, (sorry, this one is the last one for today, I promise :smiley: )

I have a final issue to resolve.


  1. Realdash is running on LeaniageOS, on RaspberryPi 4.
  2. Pi is powered before the ignition, as soon as the car security system unlocks. This is done to save some time while Pi boots.
  3. The LCD screen is powered with the ignition.
  4. My car is connected via OBDII, and gets/reads data and displays, all good.

When I turn off the car, the screen goes off, and the car ECU goes off (at least it stops responding to the OBDII). However, the Pi is still powered. When the Car is started back, the screen goes on, and Realdash is still running, but it cant seem to restore the OBDII connection unless I physically detach and reattach the USB cable.

Am I doing something wrong here?
How can I work around this?

The solution in my head is to send signals to GPIO and process them in Triggers to minimize the app into the background when the ignition is off. However, I am not sure, if it will support bringing it back to the foreground on another GPIO event.

Hard to say, maybe your OBD2 adapter goes into some kind of sleep mode and fails to boot back up? I know some adapters do that, but never encountered a situation when it would not wake up.

You still see the ‘Connecting to …’ prompt at bottom right corner?

Yes, it shows that.

Well, at least RealDash is attempting to connect to the car. Do you have an option to try another adapter?

Yes, i have some generic adapter (Also based on ELM chip) and its happening for both.

I can publik all draw and firmware for hardware reset afrer start your usb port… is you course use obd usb

Can you elaborate pls?

hi @realdashdev,

Do you think we can investigate this further?

The problem I am currently having is that I have applied a relay timer connected to ACC/IGNITION, so when I turn off my car, the power to the Pi is not shut. I catch that on Pi GPIO via trigger, and launch a shutdown -h [time] command, which is currently set to 15 mins. So that if I have a short stop, i dont have to wait for the complete boot.
That said, when I turn my car back on, I stop receiving the OBD data, such as speed, rpm etc.

attaching my OBD XML file. Could the issue be there?
Lacetti_OBD_Commands.xml (7.08 KB)

Send a debug log. Try to capture both, working and non-working situations into the log: