Up for sale is a Working, in excellent condition BMW E30 ECU.  Used, remanufactured unit. 

 Bosch Part number-- 0 261 200 402 (0261200402), BMW part number 1748401. This unit should fit some, E30 & E34 and possibly E36 325i 528i 525i models and is in good working order. This should directly replace 0261200403 and 0261200405 This may also work with other models/years but as usual check your part number off of your original to be sure it will work with your car.These units can be purchased NEW at an authorized bosch service center or your BMW dealer, however typical cost is over $2000 for a new Bosch control unit! Ouch not here! This is a good used unit here. These are even not at all easy to find good used with a warranty, at any price much less as fair as this - and we give a 30 day warranty! These are usually fairly reliable, however can easily be damaged by wiring faults or voltage spikes (caused by a faulty alternator) or just age and mileage accumulated - no electronic component lasts forever. . A faulty ECU can cause problems ranging from a bad idle control circuit to random no injector pulse signal (causes no start or random cut outs) & many others. If you need one of these units, there is no reason to spend $2000 on a new unit, get a good used one for less than you'd pay in tax alone at the dealer.