Petrol engines 2.1 ISCU
Located behind the offside rear light cluster there is a small black box called the idle stabilisation control unit.
BTW, there's lots of info on this on thesamba.com. A guy called tencentlife seems to be the guru. (Search on ISV and ISCU within the vanagon/eurovan forum): taken from this wiki entry []
The idle stabilisation control unit is an analogue circuit that outputs a pulse width modulated signal to the idle control valve. Its function is to maintain a constant idle speed while the engine is warming up and when power steering and air conditioning kicks in. As far as I can ascertain this does not make the unit engine specific and that the variations indicate circuit revisions.
I recently discovered a dry joint in mine (Rev. A) and got a spare for the road (Rev. C). Both work fine with my DJ engine with only a slight idle speed adjustment required. I investigated the different variations before buying the spare, translated information from a German forum and learnt of someone running a revision D on his DJ without problems.
However, some maintain that A and C is for DJ and B and D for MV but they do not provide a reason for this. Sensors for ISCU on DJ and MV are the same.