SFI SYSTEM (w/ Electronic Throttle Control System) ECM Power Source Circuit

DESCRIPTION

When the ignition switch is turned to ON, the battery voltage is applied to terminal IGSW of the ECM. The ECM "MREL" output signal causes a current to flow to the coil, closing the contacts of the EFI main relay and supplying power to terminal +B of the ECM.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. INSPECT ENGINE ROOM RELAY BLOCK (EFI MAIN RELAY)

   
   

   1. 

      Remove the engine room relay block.

   2. Remove the engine room relay block lower cover.

   3. Disconnect the 5 connectors from the engine room relay block.

   4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition 1C-4 - 1C-5 When battery voltage absent 10 kΩ or higher 1C-4 - 1C-5 When battery voltage applied to terminals 1C-4 and 1C-8 Below 1 Ω

   5. Reinstall the engine room relay block.

   
   

   NG

   REPLACE ENGINE ROOM RELAY BLOCK

   OK

2. CHECK HARNESS AND CONNECTOR (EFI MAIN RELAY - ECM, EFI MAIN RELAY - BODY GROUND)

   
   

   1. 

      Check the harness and connectors between the ECM and the EFI main relay.

      
      

      1. Remove the engine room relay block.

      2. Remove the engine room relay block lower cover.

      3. Disconnect the ECM connector.

      4. Measure the resistance according to the value(s) in the table below.

         Standard Resistance (Check for Open)
         Tester Connection Condition Specified Condition B26-35 (MREL) - 1C-8 Always Below 1 Ω

         Standard Resistance (Check for Short)
         Tester Connection Condition Specified Condition B26-35 (MREL) or 1C-8 - Body ground Always 10 kΩ or higher

      5. Reinstall the engine room relay block.

      6. Reconnect the ECM connector.

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

   CHECK AND REPAIR HARNESS AND CONNECTOR BETWEEN EFI FUSE AND BATTERY