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PGM-FI Main Relay Circuit Troubleshooting

  1. Turn the ignition switch OFF, then disconnect the PGM-FI main relay 7P connector.
  2. Check for continuity between body ground and PGM-FI main relay 7P connector terminal No. 3.
    Fig 1: Checking Continuity Between Body Ground And PGM-FI Main Relay 7P Connector Terminal No. 3
    G03692751Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    1. YES -  Go to step 3.
    2. NO -  Repair open in the wire between the PGM-FI main relay and G101.
  3. Measure voltage between body ground and PGM-FI main relay 7P connector terminal No. 7.
    Fig 2: Measuring Voltage Between Body Ground And PGM-FI Main Relay 7P Connector Terminal No. 7
    G03692752Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    1. YES -  Go to step  5.
    2. NO -  Go to step 4.
  4. Check for a blown ACG S (15 A) fuse in the under-hood fuse/relay box.

    Is the fuse blown? 

    1. YES -  Repair short in the wire between the PGM-FI main relay and the ACG S (15 A) fuse.
    2. NO -  Repair open in the wire between the PGM-FI main relay and the ACG S (15 A) fuse.
  5. Turn the ignition switch ON (II), and measure voltage between body ground and PGM-FI main relay 7P connector terminal No. 5.
    Fig 3: Measuring Voltage Between Body Ground And PGM-FI Main Relay 7P Connector Terminal No. 5
    G03692753Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    1. YES -  Go to step  7.
    2. NO -  Go to step 6.
  6. Check for a blown No. 2 FUEL PUMP SRS (15 A) fuse in the under-dash fuse/relay box.

    Is the fuse blown? 

    1. YES -  Repair short in the wire between the PGM-FI main relay and the No. 2 FUEL PUMP SRS (15 A) fuse.
    2. NO -  Repair open in the wire between the PGM-FI main relay and the No. 2 FUEL PUMP SRS (15 A) fuse.
  7. Push the clutch pedal in, then turn the ignition switch ON (II), and press the engine start button. Measure voltage between body ground and PGM-FI main relay 7P connector terminal No. 2.
    Fig 4: Pushing Clutch Pedal In Then Turn Ignition Switch On (II)
    G03692754Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    1. YES -  Go to step  9.
    2. NO -  Go to step 8.
  8. Check for a blown No. 21 STARTER SIGNAL (7.5 A) fuse in the under-dash fuse/relay box.

    Is the fuse blown? 

    1. YES -  Repair short in the wire between the PGM-FI main relay and the No. 21 STARTER SIGNAL (7.5 A) fuse.
    2. NO -  Repair open in the wire between the PGM-FI main relay and the No. 21 STARTER SIGNAL (7.5A).
  9. Turn the ignition switch OFF, and disconnect ECM connector A (32P).
  10. Check for continuity between PGM-FI main relay 7P connector terminal No. 1 and ECM connector terminal A15.
    Fig 5: Checking Continuity Between PGM-FI Main Relay 7P Connector Terminal No. 1 And ECM Connector Terminal A15
    G03692755Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    1. YES -  Go to step 11.
    2. NO -  Repair open in the wire between the PGM-FI main relay and the ECM (A15).
  11. Reconnect ECM connector A (32P) and the PGM-FI main relay 7P connector.
  12. Turn the ignition switch ON (II), and measure voltage between ECM connector terminals B1 and B20, and between B9 and B20 individually.
    Fig 6: Measuring Voltage Between ECM Connector Terminals B1 And B20
    G03692756Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    1. YES -  Go to step 13.
    2. NO -  Check for an open in the wires between the PGM-FI main relay and the ECM (B1, B9). If the wires are OK, replace the PGM-FI main relay.
  13. Turn the ignition switch OFF, then ON (II) again, and measure voltage between ECM connector terminals A15 and B2 within 2 seconds.
    Fig 7: Measuring Voltage Between ECM Connector Terminals A15 And B2 Within 2 Seconds
    G03692757Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there 1.0 V or less? 

    1. YES -  The PGM-FI main relay may be faulty; go to step 14.
    2. NO -  Substitute a known-good ECM (see HOW TO SUBSTITUTE THE ECM FOR TESTING PURPOSES ) and recheck. If the voltage is now normal, replace the original ECM (see ECM REPLACEMENT ).
  14. Remove the PGM-FI main relay.
  15. Connect battery power to PGM-FI main relay 7P connector terminal No. 2 and connect ground to PGM-FI main relay 7P connector terminal No. 1. Then check for continuity between PGM-FI main relay 7P connector terminals No. 5 and No. 4.
    NOTE: Use the terminal numbers shown. Ignore the terminal numbers molded into the relay.
    Fig 8: Removing PGM-FI Main Relay
    G03692758Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    1. YES -  Go to step 16.
    2. NO -  Replace the PGM-FI main relay, and recheck the circuit.
  16. Connect battery power to PGM-FI main relay 7P connector terminal No. 5, and connect ground to PGM-FI main relay 7P connector terminal No. 3. Then check for continuity between PGM-FI main relay 7P connector terminals No. 7 and No. 6.

    Is there continuity? 

    1. YES -  Go to step 17.
    2. NO -  Replace the PGM-FI main relay, and recheck the circuit.
  17. Connect battery power to PGM-FI main relay 7P connector terminal No. 6, and connect ground to PGM-FI main relay 7P connector terminal No. 1. Then check for continuity between PGM-FI main relay 7P connector terminals No. 5 and No. 4.

    Is there continuity? 

    1. YES -  The PGM-FI main relay is OK.
    2. NO -  Replace the PGM-FI main relay, and recheck the circuit.
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