There does not seem to be much clarity on the functions of a diagnostic system and what to expect when you use one. Here's a short explanation (EDIT: ok long...)


First, there are four basic types of functions that a diagnostic system can have:
- fault code reading and clearing
- service: live values and component manipulation (to check operation) or executing service routines (such as for the EPB)
- Editing the car's configuration files (CCF)
- Initializing, calibrating, or programing new components


Then you have to separate different types of faults or DTCs (Diagnostic trouble codes):
- generic OBD codes: these are all the emissions related codes that come from the drivetrain (motor and transmission). These are standardized across all manufacturers so that they can be read all over the world at emissions testing stations. There are OBD readers starting at £25 that do a fine job of reading these. Some even manage to clear fault codes.
- manufacturer specific codes: all the rest of the systems on the vehicle. In a Hyundai that is probably not too much, but in a modern LR it is quite a bit - and many items such as the EAS, ABS, DSC, etc. are vital for vehicle operation as well. These can only be read by manufacturer specific code readers.


You can separate the diagnostic systems into different categories:


- generic code readers: only emissions related OBD codes. Start at ~£25. Some of the more expensive ones may include live values (engine/trans only) and the non-generic ability to clear SRS faults (turn off airbag light) which makes them attractive for small, independent repair facilities.
- manufacturer specific fault code readers: can only read and clear faults. Shows no live values, allows no manual component activation/testing, no vehicle programming, etc. The only 'pure' fault code read/clear device for LR vehicles is the Blackbox FCR.
- manufacturer specific diagnostic systems more for personal than professional use: allow some or all of the functions of a full diagnostic system: live values, manual component activation/testing, vehicle programming, etc. Depending on the cost, these may or may not be locked to one vehicle VIN and have increasingly more functionality with increasing price. These start at the low end with the RoverAllComms (only early RR L322) and Hawkeye, and continue through our IIDTool and the Blackbox Faultmate. The latter 2 are VIN locked.
- professional diagnostic systems: these include the OEM LR IDS/SDD, Autologic, Blackbox Faultmate, and IIDTool Pro


Choosing the right system requires spending a bit of time looking at all of the relevant information. If you do not want to do any CCF editing and a a fair bit of basic maintenance on several LR's, the BBS FCR or Hawkeye might be the way to go (but be aware that the functions offered are quite basic - for instance the Hawkey can not do an EAS calibration if you replace a height sensor). If you want to do more but only on a few vehicles (say 1-3), you'll have to look into what the BBS Faultmate or IIDTool have to offer. If you have a club (or for an independent service facility) you can look into one of the professional systems.