Up for sale is a Working, in excellent condition Saab 900 Turbo Lambda Control ECU. Part number-- 0 280 800 054 (0280800054). This unit is the original for 81 82 83 & 84 900 turbos, but should fit other models of the same vintage as well, but it is the buyers responsibility to find this out. Though not nearly as complex as a modern day ECU, The way these K-Jetronic ECU's function is through adjusting the control pressure through the frequency valve based on the inputs it receives. This will alter the fuel system pressure (and amount of fuel injected) through the fuel distributor. Primarily this will affect hot and cold starting, as well as idle quality. The need for a properly functioning ECU with this system is clear!As always your best bet is to match the part numbers with the part you need. A faulty or water damaged ECU can cause a whole hots of issues with these cars, including non running, and random cutting out (but usually it will re-start moments later). Also idle control & emission issues are possible (excess smoke or overheating caused by lean running). Hot or cold start issues can be caused as well. These units are no longer available almost everywhere and VERY hard to find used. If you can find a new one, they are usually in the $1000+ range. Ouch, not here! This comes with a 30 day warranty.