Main Relay (Computer/Fuel System): Testing and Inspection

MFI CONTROL RELAY
When the ignition switch is on, battery power is supplied to the ECM, the injector, the mass airflow sensor, etc. When the ignition switch is turned on, current flows from the ignition switch through the current relay coil to ground.




CIRCUIT DIAGRAM







HARNESS INSPECTION PROCEDURES

MFI CONTROL RELAY INSPECTION
1. Check continuity of relay contacts between terminal 4 (+) and 2 (-).







If continuity exists, check continuity of relay contacts between terminal 5 and 1, with 12V power supplied to terminal 4 and terminal 2 grounded.







If continuity exists, check continuity of relay contacts between terminal 5 and 3, with 12V power supplied to terminal 4 and terminal 2 grounded.
2. If faulty, replace the MFI control relay.

MFI control relay torque: 7-11 Nm (5.2-8.1 ft.lbs.)