OVERKILL
$100 Site Donor 2021
BMW did this as well, originally you had two diag ports, one for the BMW scanner, one for OBD. Our 2000 was that way, but my M5 was all through the OBD port, but of course you needed a scanner capable of reading BMW codes to do anything remotely useful.Nissan did that well into the 2000's, Only the bare minimum of systems & data was assessable through the OBD2 port. Toyota's had their proprietary Diag Port under the hood of many early OBD2 vehicles though I can't recall using it very often......Flash out ABS codes IIRC.