Description / Abstract:
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.