Main Relay (Computer/Fuel System): Description and Operation

PURPOSE
The main relay supplies current to the fuel injectors and the idle air valve. Its primary function is to remove injection "noise" from the electrical system.

LOCATION
Attached to the left front strut tower.

NOTE: The main relay and the ignition coil relay are identical. Check relay wiring to determine which relay you are dealing with.
The main relay wires are:
Red
Blue/Yellow
Green/Red
Black
The ignition coil relay wires are:
Red
Green/Orange
Black
Black

OPERATION
Battery voltage is applied to terminals 2 and 3 at all times. When the ECU grounds terminal 1, the relay supplies current to the injectors and idle air valve via terminal 4.