i see, ill have a look at what makes a LCD suitable for automotive , maybe that's why i haven't been able to get any hits, i was searching the wrong terms.
The device is not safety related, but it does interfere with the engine operation in some way. there shouldn't be any danger unless critical sings of engine issues are ignored.
worst case scenario is that the engine will slowly start dying and then stall, and may cause engine damage, this would require the user to ignore all signs of the malfunctions till they got out of hand which would take at least a few minutes ( the CEL would be flashing in this case).
best case scenario, nothing happens and device just doesn't function.
there was sufficient thought (IMO) in the coding to check that all sensors are operating within expected ranges before doing anything, and if desired response from the system doesn't match with predicted, it just stops.
similar logic was put into the electronics , is was setup so that if everything fails on my device, it wouldn't propagate back to the car, but any issues with the car would most likely cause the software to stop my devices function and possibly burn the electronics of my device.