Component Tests and General Diagnostics

Operation

While the ignition switch is ON, battery power supply is supplied to the engine control module, injectors, volume air flow sensor, etc.

When the ignition switch is switched ON, current flows from the ignition switch, via the MFI relay coil to ground.

As a result, the MFI relay switch is switched ON, and power is supplied, by way of the MFI relay switch, from the battery to the engine control module.





Inspection






Harness Inspection



Multiport Fuel Injection Relay Inspection





(1) Remove the multiport fuel injection relay.
(2) Check the continuity between the multiport fuel injection relay terminals.








(3) Use jumper leads to connect multiport fuel injection relay terminal 7 to the battery (+) terminal and terminal 5 to the battery (-) terminal.

Caution: When connecting the jumper leads, be careful not to mistake the connection terminals, as damage to the relay will result.





(4) Check the Voltage at multiport fuel injection relay terminal 1 while connecting and disconnecting the jumper lead at the battery (-) terminal.
(5) Use the jumper leads to connect multiport fuel injection relay terminal 8 to the battery (+) terminal and terminal 6 to the battery (-) terminal.








(6) Check the continuity between multiport fuel injection relay terminals 2-4 and terminals 3-4 while connecting and disconnecting the jumper lead at the battery (-) terminal.
(7) If there is a defect, replace the multi port fuel injection relay.

Engine Control Module Power and Ground







Operation

Grounding of the engine control module.

Troubleshooting Hints

If there is incorrect or incomplete contact of the engine control module's ground line, the engine control module will not function correctly.




Harness Inspection