1. Scope--This SAE Information Report describes the diagnostic data communications required for implementation of a set of diagnostic test modes for all electronic systems on the vehicle's serial data link. These test modes can be used by off-board test equipment for both service and assembly plant testing.

The goal of this document is to provide standard methods to perform common functions for all electronic systems. This standard set of procedures will aid development, production, and field service of those systems. Use of the standard data communications in this specification will potentially result in the following benefits:

Common methods and procedures for developers to use, without the need to invent methods to perform these functions

Common programming techniques for system programmers, with increased sharing of software procedures

Common hardware, software and test procedures for assembly plant testing

Common hardware, software and service procedures for service diagnostics across different vehicle manufacturers and systems

This specification includes:

Diagnostic Message Formats Device ID's Functional descriptions of all diagnostic test modes Message and response formats for all diagnostic test modes

1.1 Purpose--The diagnostic test modes (DTM) provide off-board test equipment with communication access to the on-board vehicle electronic systems. The off-board equipment shall be able to interrogate the electronic systems on the vehicle, and exercise control over these systems for the purposes of verifying system operation and diagnosing malfunction conditions.

Diagnostic test modes are predefined and standardized for all systems on the vehicle. Each device on the vehicle will implement only those DTMs which are appropriate for that device. Not all modes will be implemented on each device. If use of these modes is not appropriate for a given application, or during some operating modes, then that device is responsible to verify safe and proper operation and not respond to the request.