Editing On-board diagnostics (section)

=== Driver's supplementary vehicle instrumentation ===

'''Driver's supplementary vehicle instrumentation''' is instrumentation installed in a vehicle in addition to that provided by the vehicle manufacturer and intended for display to the driver during normal operation. This is opposed to scanners used primarily for [[active fault]] diagnosis, tuning, or hidden data logging.

Auto enthusiasts have traditionally installed additional gauges such as manifold vacuum, battery current etc. The OBD standard interface has enabled a new generation of enthusiast instrumentation accessing the full range of vehicle data used for diagnostics, and derived data such as instantaneous fuel economy.

Instrumentation may take the form of dedicated [[trip computer]]s,<ref>[[OBDuino]] open source OBD trip computer</ref> [[carputer]] or interfaces to [[Personal digital assistant|PDAs]],<ref>{{Cite web|date=2020-12-15|title=Advantages and Disadvantages of Personal digital assistant|url=https://www.geeksforgeeks.org/advantages-and-disadvantages-of-personal-digital-assistant/|access-date=2021-11-22|website=GeeksforGeeks|language=en-us}}</ref> smartphones, or a [[Garmin]] navigation unit.

As a carputer is essentially a PC, the same software could be loaded as for PC-based scan tools and vice versa, so the distinction is only in the reason for use of the software.

These enthusiast systems may also include some functionality similar to the other scan tools.