Overall mileage isn’t a standard PID available in the OBDII world. I think the only way it could be read on a Z3 is directly from the cluster but I don’t know of any tool that can do this.I use a Creator scanner to check things on the OBD occasionally.
Is there a true mileage (or in kms) register in the OBD that another type of scanner or INPA can read?
I've seen this on other cars but they were of a later manufacture.