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My '05 Holden has multiple buses and I imagine every car of that era and beyond is the same. One is OBD-2 and accessible under the steering wheel. It _only_ h
by qbasic_forever 5y ago
My '05 Holden has multiple buses and I imagine every car of that era and beyond is the same. One is OBD-2 and accessible under the steering wheel. It _only_ has the mandated emissions equipment info connected to it, like oxygen sensor readings and such.
It has an entirely separate and different physical connector for a CAN bus, one in the engine bay and another under the driver seat IIRC. This one has all the goodies--locks, entertainment system, full engine diagnostics and sensors, etc. I actually have the full factory service manual for the car and key programming is only possible with GM's tech 2 computer system connected to the CAN bus, not OBD-2.
- bri3d 5y agoThis split-connectors model is actually quite uncommon. Many newer cars have either a single CAN bus, a "Gateway" module which bridges Diagnostic CAN accessible through the OBD port to the various CAN buses used inside of the car, or Ethernet / DoIP exposed over "unused" pins on the OBD connector. For example, on modern VW AG cars, key programming is performed over the OBD connector, using specific UDS readLocalIdentifier and writeLocalIdentifier requests, but the data involved in the Immobilizer is both signed and encrypted using secret keys on a VW server (called FAZIT) over a subscription system called GeKo. The dealer diagnostic tool essentially sets up a tunnel over UDS between the Immobilizer software module in a control unit and the FAZIT server.