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

Power Supply and Ignition Switch






Circuit Diagram






ECM connector view

Operation

If the ignition "ON" signal is input, ECM flows electricity to the multiport fuel injection relay coil to turn on the power supply switch. This circuit also supplies power to the injector, volume air flow sensor, idle air control motor, etc.

Inspection

Using Scan tool






Harness Inspection




















Multiport Fuel Injection Relay Inspection

1. Remove Multiport fuel injection relay.






2. Use jumper wires and connect multiport fuel injection relay terminal 10 to the battery B+ terminal and terminal 8 to the battery B- terminal.

Caution: Be very careful when connecting the jumper wires because the relay will be damaged if a mistake is made with the contact terminals.






3. With battery B- terminal jumper wire connected and disconnected, measure the Voltage at multiport fuel injection relay terminals 4 and 5.






4. Use jumper wires to connect multiport fuel injection relay terminal 9 to the battery B+ terminal and terminal 6 to the battery B- terminal.






5. Disconnecting the jumper wire on the terminal B- side of the battery, check whether or not continuity exists across terminals 2 and 3 of the multiport fuel injection relay.






6. Use jumper wires and connect multiport fuel injection relay terminal 3 to the battery B+ terminal and terminal 7 to the battery B- terminal.






7. With battery B- terminal jumper wire connected and disconnected, measure the Voltage at multiport fuel injection relay terminal 2.
8. Replace multiport fuel injection relay if faulty.