tr Jaguar XJ6 ECU Up for sale is a Working, in excellent condition Jaguar XJ6 ECU. Part number-- DBC5702 84781-D . This unit is out of an XJ6 4.0 liter, my list shows this fits many 90-92 year Jaguar 6 cyl cars. your best bet is to match the jaguar part number up with the unit you are replacing. A faulty ECU is one of the primary causes of false check engine lights, intermittent no start or random cut out. Sometimes these will lose injector pulse (no fuel injector function / no start) These units now have to be special ordered from most dealers new for big $$ (often times over $1000!), and finding a good one second hand is getting to be chore.