Main Relay (Computer/Fuel System): Testing and Inspection
MFI CONTROL RELAYWhen the ignition switch is turned on, battery voltage is applied from the ignition switch to the ECM, turning ON the ignition power transistor and energizing the MFI control relay coil. This turns ON the MFI control relay switch, and supplies power from the battery to the ECM through the MFI control relay switch.
CIRCUIT DIAGRAM
USING GST
HARNESS INSPECTION PROCEDURES
MFI Control Relay Inspection
NOTE: When applying battery voltage directly, make sure it is applied to the correct terminal. Otherwise, the relay could be damaged.
1. Connect a 12V power supply (+) terminal to terminal 6 of the MFI control relay and measure the voltages at terminal 1 when the (-) terminal is connected to and disconnected from the terminal 8.
2. Connect a 12V power supply (-) terminal to terminal 10 of the MFI control relay and check the continuity between terminals 3 and 4 when the (+) terminal is connected to and disconnected from the terminal 7.
3. Connect a 12V power supply (+) terminal to terminal 3 of the MFI control relay. Measure the voltages at terminal 4 when the (-) terminal is connected to and disconnected from the terminal 9.
4. If one of the above is improper, replace the MFI control relay.