Datsun / Nissan 240 SX ECU Up for sale is a Working, in excellent condition 1990 Datsun / Nissan 240 SX Engine fuel / engine control module. Part number-- A11-B99 G54 73 Unit , This ECU came out of a 90, But my list shows this fits some 89-90 models. As always your best bet is to match the part number to the one on your original ECU. These units have been NLA for quite a while now, and are not at all easy to find, at any price much less as fair as this. These are usually fairly reliable, however can easily be damaged by wiring faults or voltage spikes (caused by a faulty alternator). 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. Normally these are well over $600 for rebuilt, even more new. Get a good working used one here for a LOT less money.