tr Lexus / Toyota LS-400 V8 ECU Up for sale is a Working, in excellent condition Lexus LS-400 V8 ECU. Denso Part numbers listed at top 89661-50020 LS-400 ENGINE. This unit offers a 30 day functionality warranty. As always with this type of component your best bet is to match the part number to the one on your original ECU as there are a few different variants you might have. A faulty ECU is one of the most common no start or random stalling problems with these cars. These can also cause issues with erroneous check engine lights, idle control problems as well as emission control & cold or hot start problems. I have also seen fuel pump relay turn on faults (ECU won't turn on the fuel pump), as well as an condition where the high speed injector driver has failed. This causes the car to sit and idle fine, but it won't accelerate.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 one when you need one. Even now finding a good one second hand is getting to be quite difficult as these cars get older.