LS 400 V8-4.0L (1UZ-FE) (1990)
Fuel Pump Relay: Description and Operation
Circuit Opening Relay
Circuit Opening Relay Schematic
PURPOSE
The circuit opening relay provides power to the fuel pump.
LOCATION
Mounted to the ECU behind the right side of the dash.
CONSTRUCTION
The relay consists of a single set of contacts controlled by two separate coils.
OPERATION
One coil is energized when the key is turned to the start position. The relay contacts close and power is supplied to the fuel pump for starting.
Once the ECU begins to receive pulses from the engine rpm sensor it grounds the other coil which continues to hold the contacts closed after the
key is released to the run position.