So Anyway, techstream is working now.
Can anyone tell me why there is a port under the bonnet if it doesn't work?
@Wilsil has covered it -- but I looked up my files -- and as usual there is "too much information" but here it is anyway!!
On many (?) most (?) all (?) 100 series vehicles (LC100 and LC105 and LX470) there exists
- Diagnostic Link Connector 1 (DLC1) -- socket in the engine bay above RHS front wheel arch with a cap marked "DIAGNOSTIC" and pin-out 'map' on the inside surface of the cap (more about that later),
and,
- Diagnostic Link Connector 3 (DLC 3) -- socket near the brake pedal, pin-out map may appear in Factory Service Manuals (FSM) or search the internet.
DLC2, if there is one on LC100/LX470, remains mystery at least to me. DLC2 does appear on some other Toyota vehicles.
Pin-outs, meaning location and purpose of pins, and programming of the relevant Electronic Control Units (ECU) may vary somewhat across models, years and markets -- because
(i) different countries and jurisdictions have somewhat different requirements as to pollution controls, particularly as to timing of implementation as determined by Governments, and,
(ii) other features vary across models, years and markets as determined by manufacturers and/or customers. Nevertheless, some common standards are used internationally.
The OBD thing ....
This had its origins in pollution control and regulation, initially in Europe and USA and then elsewhere, and involved standards for software, connectivity and wiring, including the style of socket and plug which is called DLC3 on 100 series vehicles, and also is used widely on other vehicles.
Given that the basic environmental requirement was mandatory anyway, other wider diagnostic uses also evolved.
In Australia, requirements are imposed on importers and manufacturers concerning exhaust and evaporative emissions requirements for light vehicles in order to reduce air pollution. Among these, compliance with Australian Design Rule (ADR) 79/01 and 79/02 is required. Details can be found at
Vehicle Standard (Australian Design Rule 79/01 — Emission Control for Light Vehicles) 2005 - https://www.legislation.gov.au/Details/F2005L04080. This is the "OBD2 Standard" for Australia. Except for commencement dates, it borrows from similar standards elsewhere in the world.
In practice, the Australian standard is equivalent to the US-based OBD II SAE J-2012 standard, including its technical implementation and the use of a data link connector that complies with the SAE J-1962 standard, which describes the 16-pin data link connector which we know as DLC3.
The various standards that define OBD II technology allow car manufacturers in different markets to adapt the operating parameters of systems such as Engine Management, ABS, Stability Control, Active Suspension and others to match the operation of these systems to particular markets and models, evolving over time.
The different programming of some systems between markets does not represent a departure from the basic definitions of OBD II fault codes, nor does it represent an evolution of how OBD II systems track and report faults.
The dates for compliance with Australian Design Rule (ADR) 79/01 and 79/02 -- see above link and also second attachment below -- are why @Wilsil was correct to remind me that "OBD2" was
not a requirement on new vehicles in Australia at the same time as it may have been required in the USA or EU or UK or elsewhere. Some importers/manufacturers may have fitted "OBD2" in advance of Australian legislative requirements because that may have simplified global manufacturing of their systems, wiring looms etc.
So what about Diagnostic Link Connector 1 (DLC1) -- socket in the engine bay above RHS wheel arch with a cap marked "DIAGNOSTIC" and pin-out 'map' on the inside surface of the cap??
This is a proprietary Toyota/Lexus "thing" installed for purpose of diagnosis of multiple systems from the engine bay. @Wilsil does not mean that it does not work, only that it is configured differently for other purposes and it will not work with the commonly available Techstream aftermarket cables, not least because the socket and plug are not compatible. Adapters to the 16-pin "OBD2" plug are easily found on via
eBay and elsewhere but I have never tried them.
DLC1 is useful as it is without an adapter for a range of purposes. Of interest in the AHC/TEMS systems, DLC1 can be used directly without Techstream as described in the first attachment below for a range of basic and important tests -- which deserve routine maintenance and diagnostic attention but which often are overlooked!
With the evolution of the mandatory OBD systems, the same tests also can be conducted via DLC3 with slightly different connection instructions as set out in updated Factory Service Manuals (FSM's) -- including the FSM references in Post #6 in this thread.
The advantage of the DLC1 method and facility is simply convenience and visibility in the engine bay compared with scrambling around under the dashboard. This is particularly helpful for the "Height Control Operation Test" alias
"Active Test", useful when adjusting 'ride height' and adjusting Height Control Sensors, amongst other things.
The tests in the attachment below specify Toyota/Lexus Special Service Tool SST 09843-18020 -- which is a simple connector wire and can be purchased from a Dealer -- but an unbent paperclip works just as well!
DLC1 on 2006 LC100 Sahara with AHC:
DLC3 on 2006 LC100 Sahara with AHC:
