Oh - and if your concern is that Scanguage didn't work, therefore maybe Techstream won't work, I found these two lists of Scanguage II Australian Vehicle compatibility and it looks like LX470 2006 and up and LC2003 and up are supported, but lots of vehicles are not. However it's not clear to me if Techstream would not work for the same reason... See my update below on why Scanguage doesn't work with all the same vehicles years as in US - b/c of lack of OBD2 support...
ScanGaugeII - Compatible Vehicle List for Australia - Toyota
ScanGaugeII - Compatible Vehicle List for Australia - Lexus
UPDATE:
Actually just found two more explanations:
1) From here
http://www.ample-outdoors.com.au/store/faq.php?cID=1
Does the Scangauge II work in my vehicle?
A list of compatible Australian vehicles is being compiled by our staff through direct testing and using customer feedback. This list is continually being updated and is available online here.
Understanding OBD2 in Australia.
In Australia OBDII compatibility was finally made compulsory in January 2006 by new requirements in the Australian Design Rules. Vehicles made between 1997 & 2006 may or may not be OBDII compatible. Because the ADR did not require an active OBDII system in Australia before 2006, some vehicle manufacturers did not implement it.
Tracking down exactly when particular vehicles began using OBDII in Australia is a time cosuming task. At this time most vehicles we have tested the ScanGauge II on do work, but there are a few that do not.
Please view our compatibility list here. NOTE: If your vehicle is not included in our list it does not mean that it will not work, just that we have not directly tested the ScanGaugeII or had a customer report compatibility on your type of vehicle. We suggest you conduct a google search with keywords of ScanGauge and your vehicle model and year. Google search results will usually lead to some online message forums where users have discussed compatibility with your vehicle.
If in doubt, call us before making your purchase!
Due to the ScanGaugeII's new heat sealed blister packaging returns can no longer be accepted due to incompatibility with your vehicle, so once again.....research or ask us before purchasing!
We can arrange a time to test the Scangauge II on your vehicle at our offices in Clarence NSW. If you wish to organise a time to do so, please call us on 1300 796 960. We also have a number of demo units we can send out to customers if they would like to confirm compatibility with a vehicle that we do not have compatibility information on. Call us to arrange a demo unit to be posted out to you.
2)
"View Our Australian Vehicle Compatibility List The ScanGauge requires the vehicle to be either OBDII or EOBD compatible. In the US and Canada, cars and light trucks were required to be OBDII compatible starting in 1996. In Europe, EOBD was phased in between 2002 and 2004. Other parts of the world have required one of them starting in various years. Many vehicles made and/or sold outside the US and Canada had one of the protocols before they were required in that country. This was to allow sales to other countries and because they knew they would eventually be required to meet the requirements and designed it in when they redesigned a particular model. There is no comprehensive list of when particular vehicles began using OBDII or EOBD in Australia. At this time most vehicles we have tested the ScanGauge II on do work, but there are a few that do not. For example the ScanGauge II does not work on most pre 2005 Toyota four wheel drives. It should be noted the ScanGaugeII does not work..." from here:
http://www.experts123.com/q/will-the-scangauge-ii-work-on-vehicles-in-australia.html