LSing

First: Is there a fuel pump ecu in an LS4hundred 1991?
Second: Where is the fuel pump ecu?

It is clear that there is a fuel pump in an SC model vs. LS model

sahtt

Your question is unclear but I'll try. The sc4 and ls4 have more or less identicle fuel systems. They both have fuel pump ECU's and the LS400's is located in the trunk, on the left side against the wall. I am 99% sure the SC's is in the same location but I haven't actually owned the car (yet). Try looking here for more specifics lexus ls400 fuel pump.

CK6Speed

iTrader: (1)

The fuel pump ECU in the SC300/400 is located on the left side (Drivers side) of the car behind the rear 1/4 panel right under the rearl 1/4 panel window area. To get to the fuel pump ECU on the SC, you have to remove the rear seats so you can remove the rearl 1/4 panel. Common failure on the SC, so I would assume common failure on the early LS as well. It is a 2 state ECU puttin allowing the fuel pump to opporate on low volate, or high voltage (Full 12V) when needed. A lot of us that have had fuel pump failures on our SC's simply bypassed the low stage that fails and directing 12V diretly to the fuel pump all the time. The Fuel Pump ECU is not so much an ECU but more like a smart relay.