VW 1.8T ECU 1999 1998 Up for sale is a Working, in excellent condition VW Volkswagen passat / Audi A4 1.8T ECU. VW part # 8D0 907 557 P  /   557P , Bosch part # 0 261 204 258. This ECU should fit most 1998-1999 1.8 turbo cars. Please check the part number off of your original unit to be sure if this is correct for your car, as there are some in the this range that are NOT the same as this. This unit offers a 30 day functionality warranty. A faulty ECU is one of the most common no start, starts but stops running, or random stalling problems with these cars. These can also cause issues with erroneous check engine lights as well as emission control malfunctions & cold or hot start problems. Though generally fairly reliable these problems can sometimes "just happen"If your car does not have these issues but you intend to keep it a while, I recommend our customers keep an extra ECU in the trunk. These units now have to be special ordered from most dealers new for big $$ (often times over $1000!), and you can never find the right one when you need one. Even now finding a good one second hand is getting to be quite difficult as these cars get older. These are also fantastic to have if you are doing a chip upgrade, and want to keep your original program.