Mercedes 300E 300TE ECU Up for sale is a Working, in excellent condition Mercedes 300E 300TE ECU. These commonly cause problems due to their location (they can be water damaged) or can suffer damage by voltage spikes. Should fit many 1987-1989+ 300 models. ECU. Part number-- 005545723 Be sure to check the part number off of your old one to be sure this is correct. Offers a 30 day guarantee. Thanks for looking!