Hi, so glad I've come across this forum as it's the kind of detailed technical level I'm looking for.

So first complete NOOB question - can someone explain to me in plain language to begin, how are EGRs disabled properly when the whole EGR is removed and so the plug is disconnected. I have fitted a bypass kit to my BMW E70 LCI and of course that has now set a number of DTCs relating to the EGR and associated cooler. Using ISTA diagnostics I see that one of these sets the MIL: 4CAE EGR Controller Position Sensor Signal.

I have been playing around with an ORI file from the same vehicle (haven't got a way to dump my actual DDE yet) and I've looked at what happens if software is used to simply disable the DTC by comparing ORI and modified in IDA. I can see that 3 bytes are changed to turn off the 4CAE.

What I want to know is the actual correct way to disable the EGR, as in stop the ECU logging the fault in the first place rather than just applying 00 and FF in a few places to suppress the warning I understand that maps can be modified, but that wouldn't help in cases where the whole EGR is removed.

Note that I would also like to know how in general terms a fix would apply to the EGR cooler errors too, which are set for temp sensor and bypass valve (not causing a MIL though)

Hope that makes sense - I am trying to learn how to do things and understand how the systems work rather than just masking the problem by disabling a bunch of DTCs

Thanks for reading!