The Autocheck Computer
On account of the fact that the Autocheck computer was used on many 80/90 models of various engine sizes, weights and country specific variations, Audi took the wise approach of a modular design for the Autocheck system. This is much cheaper (and easier logistically) than producing specific systems for each country and/or engine and/or chassis type.
This material is fluid right now as I am still in the process of collating it, but here is some info, hints and allegations that are of interest...
First off, there are at least two physical variants of the Autocheck computer module that are applicable to the S2. Despite all the modularity designed into them - the LCD modules have a printed legend relative to Miles & Gallons (for the British Isles) or Kilometres & Litres (for everywhere else). My investigations are with the 'GB' coded Autocheck system, but I fully expect there to be other secrets with respect to cars destined for other regions. The table below gives part numbers of known Autocheck systems.
Now things get really interesting, because although the S2 was never imported to the USA, it uses the exact same Autocheck computer model (a532) as the 20V Coupe Quattro which did make it's official way to North America. Now you'd think that because the Brits and the Yanks speak the same lingo and have resisted all attempts to understand kilometres, they would have the same Autocheck configuration... but you'd be wrong because imperial gallons (used in the UK) are larger than US gallons!
Consequently the trip computer has to make adjustments to fuel calculations accordingly. The way it does this is via a 'coding plug' which is inserted into an 11-pin connector on the Autocheck module.
It is the use of this coding plug inserted into the Autocheck module which provides it with information on the vehicle model and destination country that defines how the module behaves in any given application. The code plug, residing on the left edge of the instrument cluster, is shown in the figure below.
The table below details some known coding plugs from various 80/90 vehicles & countries. Eventually I hope to work out how to modify the UK-S2 code plug to enable the MIL bulb (as used on Californian cars) but retain the use of imperial gallons for fuel and range calculations. UPDATE - this simple mod is now working on my car for built-in blink code display :) It transpires that the coding plug has nothing to do with this functionality whatsoever. Details are here ...
There are plenty of other code plugs applicable to the Autocheck system. I would be delighted to add such details onto this part of the site - particularly from S2 owners outside of the UK - Please Email your codeplug part numbers if you can spare a few minutes to remove your instrument cluster. The Audi parts database does not list all of the country specific plugs so I need them from real cars so I can continue with the reverse engineering...
The code plug versions I imagine for the S2 should be for Saudia Arabia (SA), Europe (EU) and Japan (JA). Perhaps the South African and Australisian cars had their own code plugs too ?
Thanks to Maarten
Reinders for the EU code plug info.
Well I think that is it's main purpose, but it could also be thought as an option switch which may do different things depending on the code plug that is being used.
WARNING - If attempting this, you are completely on your own for any damage caused to your car. All I have described here is what happens on my car - a 1994 S2 Coupe (UK). You should only move the sliding switch with the ignition OFF.
I also noted that the US position provides
a slight difference in the Autocheck
. Photos to follow, but the US position lacks the hydraulic/brake system
warning symbol at the start of the display test routine for reasons unknown
- maybe the US market dictates that such a fault must only be reported by
the most simple of means in the form of a computer-free warning bulb ?
Last Updated 24th November 2002