I have found that any component directly connected to the BMW motor, such as boost or IAT, operates on the 1 Mbps CAN bus. When I try to read this in some mode, the car freaks and starts showing errors on my infotainment screen. Others will not return data. Is there any way to listen to the data without the car knowing and throwing codes?
This is on a 2018 bmw F22 M240i
By default, RealDash does not send anything to the CAN bus unless an Action has been configured to change the data, or any of the frames have been marked with writeInterval on XML.
So in that sense, this seems like adapter configuration error, or CAN bus resistance issue when new adapter is introduced to the bus.
CAN termination is a key point, and the CAR’s CAN system is already terminated as they designed, if you adds an external device your device also requred an small termination due the wire chunk. Your CAN device can be tarminated as showed on the image, this will be tolareted by the CAR network. The values optimal at 500Kbit, in your case the 4.7nF cap may need to be lowered..
