Central Diagnostic Firewall: Isolating OBD-II Ports from Safety-Critical Powertrain & Steering Buses

Mandatory emissions regulations require vehicles to expose an open OBD-II diagnostic port. However, bridging this physical port directly to vehicle CAN buses creates a severe vulnerability: malicious dongles or compromised diagnostic tools can broadcast arbitrary commands.

The Central Diagnostic Gateway acts as an application-level firewall. It inspects all incoming UDS requests: • Read-only standard emissions PIDs (01-09) are forwarded to the powertrain bus. • Enhanced proprietary diagnostic commands are dropped unless the connection is mutually authenticated. • Cross-bus frame spoofing is prevented by physical routing isolation.