This part of ISO 15031 gives guidelines for the protection of road vehicle modules from unauthorized intrusion through a vehicle diagnostic data link. These security measures offer vehicle manufacturers the flexibility to tailor their security to their own specific needs, and do not exclude other, additional measures.

This part of ISO 15031 applies to vehicle modules whose solid-state memory contents are able to be altered from outside the electronic module through a diagnostic data communication link. Such alteration could potentially damage a vehicle's electronics or other components, placing at risk its compliance with government legislation or the vehicle manufacturer's interests in respect of security.