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Home >> Honda >> 2003 >> Civic Si >> Repair and Diagnosis >> Engine Performance >> System >> PGM-FI System (Hatchback) >> MIL Circuit Troubleshooting

MIL Circuit Troubleshooting

  1. Connect the HDS or a scan tool (see HOW TO USE THE HDS OR A SCAN TOOL ).
  2. Turn the ignition switch ON (II) and read the HDS or a scan tool.

    Does the HDS or a scan tool communicate with the ECM? 

    YES:  Go to step 3.

    NO:  Go to troubleshooting "DLC Circuit Troubleshooting" (see DLC CIRCUIT TROUBLESHOOTING ).

  3. Check the HDS or a scan tool for DTCs.

    Are any DTCs indicated? 

    YES:  Go to the DTC TROUBLESHOOTING INDEX .

    NO:  Go to step 4.

  4. Turn the ignition switch OFF.
  5. Turn the ignition switch ON (II) and watch the malfunction indicator lamp (MIL).

    Does the MIL come on and stay on for more than 20 seconds after turning the ignition switch ON (II). 

    YES:  If the MIL always comes on and stays on, go to step 76. But if the MIL sometimes works normally, first check for these problems.

    • An intermittent short in the wire between the ECM (E29) and the data link connector (DLC).
    • An intermittent short in the wire between the ECM (E31) and the gauge assembly.

    NO:  If the MIL is always off, go to step 6. But if the MIL sometimes works normally, first check for these problems.

    • A loose No.10 METER (7.5A) fuse in the under-dash fuse/relay box.
    • A loose No.20 IG (40A) (Canada: 50A) fuse in the under-hood fuse/relay box.
    • A loose No.6 ECU (ECM)(15A) fuse in the under-hood fuse/relay box.
    • A loose No. 17 FUEL PUMP (15A) fuse in the under-dash fuse/relay box.
    • A poor connection at ECM terminal E31.
    • An intermittent open in the GRN/ORN wire between the ECM (E31) and the gauge assembly.
    • An intermittent short in the wire between the ECM (A21) and the manifold absolute pressure (MAP) sensor.
    • An intermittent short in the wire between the ECM (A20) and the throttle position (TP) sensor.
    • An intermittent short in the wire between the ECM (E5) and the fuel tank pressure (FTP) sensor.
  6. Turn the ignition switch OFF.
  7. Turn the ignition switch ON (II).

    Is the low oil pressure light on? 

    YES:  Go to step  10.

    NO:  Go to step 8.

  8. Inspect the No.10 METER (7.5A) fuse in the under-dash fuse/relay box.

    Is the fuse OK? 

    YES:  Go to step 9.

    NO:  Repair short in the wire between No.10 METER (7.5A) fuse and the gauge assembly. Also replace the No.10 METER (7.5A) fuse.

  9. Inspect the No. 20 IGI (40A) (Canada: 50A) fuse in the under-hood fuse/relay box.

    Is the fuse OK? 

    YES:  Repair open in the wire between the No.20 IG(40A)(Canada: 50A) fuse and the gauge assembly. If the wire is OK, test the ignition switch (see TEST ).

    NO:  Repair short in the wire between No.20 IG (40A) (Canada: 50A) fuse and the under-dash fuse/relay box. Also replace the No.20 IG(40A) (Canada:50A) fuse.

  10. Try to start the engine.

    Does the engine start? 

    YES:  Go to step 11.

    NO:  Go to step  14.

  11. Turn the ignition switch OFF.
  12. Connect ECM connector terminal E31 to body ground with a jumper wire.
    Fig 1: Connecting ECM Connector Terminal E31 To Body Ground With A Jumper Wire
    G01399427Courtesy of AMERICAN HONDA MOTOR CO., INC.
  13. Turn the ignition switch ON (II).

    Is the MIL on? 

    YES:  Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck (see ECM UPDATING AND SUBSTITUTION FOR TESTING ). If the symptom/indication goes away with a known-good ECM, replace the original ECM.

    NO:  Check for an open in the wire between the ECM (E31) and the gauge assembly. Also check for a blown MIL bulb. If the wires and the bulb are OK, replace the gauge assembly.

  14. Turn the ignition switch OFF.
  15. Inspect the No.6 ECU (ECM)(15A) fuse in the under-hood fuse/relay box.

    Is the fuse OK? 

    YES:  Go to step  22.

    NO:  Go to step 16.

  16. Remove the blown No.6 ECU (ECM) (15A) fuse from the under-hood fuse/relay box.
  17. Remove the glove box (see GLOVE BOX REMOVAL/INSTALLATION ) and PGM-FI main relay 1.
    Fig 2: Removing PGM-FI Main Relay 1
    G01399428Courtesy of AMERICAN HONDA MOTOR CO., INC.
  18. Check for continuity between body ground and PGM-FI main relay 1 4P connector terminals No.2 and No.4 individually.
    Fig 3: Checking For Continuity Between Body Ground And PGM-FI Main Relay 1 4P Connector Terminals No.2 And No.4 Individually
    G01399429Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES:  Repair short in the wire between the No.6 ECU (ECM)(15A) fuse and the PGM-FI main relay 1. Also replace the No.6 ECU (ECM)(15A) fuse.

    NO:  Go to step 19.

  19. Disconnect each of the components or the connector below, one at a time, and check for continuity between PGM-FI main relay 1 4P connector terminal No.1 and body ground.
    • PGM-FI main relay 2
    • ECM connector A (31P)
    • Each injector 2P connector
    • Idle air control (IAC) valve 3P connector
    • Camshaft Position (CMP) sensor B 3P connector
    • Crankshaft position (CKP) sensor 3P connector
      Fig 4: Checking For Continuity Between PGM-FI Main Relay 1 4P Connector Terminal No.1 And Body Ground
      G01399430Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES:  Go to step 20.

    NO:  Replace the component that made continuity to body ground go away when disconnected. If the items is the ECM, update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck (see ECM UPDATING AND SUBSTITUTION FOR TESTING ). If the symptom/indication goes away with a known-good ECM, replace the original ECM.

    Also replace the No. 6 ECU (ECM) (15A) fuse.

  20. Disconnect the connectors of all these components.
    • PGM-FI main relay 2
    • ECM connector A (31P)
    • Injectors
    • Idle air control (IAC) valve
    • Camshaft Position (CMP) sensor B
    • Crankshaft position (CKP) sensor
  21. Check for continuity between PGM-FI main relay 1 4P connector terminal No.1 and body ground.
    Fig 5: Checking For Continuity Between PGM-FI Main Relay 1 4P Connector Terminal No.1 And Body Ground
    G01399431Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES:  Repair short in the wire between PGM-FI main relay 1 and each item. Also replace the No.6 ECU (ECM)(15A) fuse.

    NO:  Replace PGM-FI main relay 1. Also replace the No. 6 ECU (ECM) (15A) fuse.

  22. Inspect the No.17 FUEL PUMP (15A) fuse in the under-dash fuse/relay box.

    Is the fuse OK? 

    YES:  Go to step 34.

    NO:  Go to step 23.

  23. Remove the blown No.17 FUEL PUMP (15A) fuse from the under-dash fuse/relay box.
  24. Disconnect ECM connector E (31P).
  25. Check for continuity between ECM connector terminal E9 and body ground.
    Fig 6: Checking For Continuity Between ECM Connector Terminal E9 And Body Ground
    G01399432Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES:  Go to step 26.

    NO:  Replace the No. 17 FUEL PUMP (15A) fuse, and update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck (see ECM UPDATING AND SUBSTITUTION FOR TESTING ). If the symptom/indication goes away with a known-good ECM, replace the original ECM.

  26. Remove the PGM-FI main relay 2 (A).
    Fig 7: Removing The PGM-FI Main Relay 2
    G01399433Courtesy of AMERICAN HONDA MOTOR CO., INC.
  27. Check for continuity between ECM connector terminal E9 and body ground.
    Fig 8: Checking For Continuity Between ECM Connector Terminal E9 And Body Ground
    G01399434Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES:  Repair short in the wire between the No.17 FUEL PUMP (15A) fuse and the ECM (E9), or between the No.17 FUEL PUMP (15A) fuse and the PGM-FI main relay 2. Also replace the No.17 FUEL PUMP (15A) fuse.

    NO:  Go to step 28.

  28. Remove the rear seat cushion (see REAR SEAT REMOVAL/INSTALLATION ).
  29. Remove the access panel from the floor.
  30. Disconnect the fuel pump 5P connector.
  31. Check for continuity between fuel pump 5P connector terminal No. 5 and body ground.
    Fig 9: Checking For Continuity Between Fuel Pump 5P Connector Terminal No. 5 And Body Ground
    G01399435Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES:  Repair short in the wire between the fuel pump and PGM-FI main relay 2. Also replace the No. 17 FUEL PUMP (15A) fuse.

    NO:  Go to step 32.

  32. Reinstall PGM-FI main relay 2 (A).
    Fig 10: Reinstalling PGM-FI Main Relay 2
    G01399436Courtesy of AMERICAN HONDA MOTOR CO., INC.
  33. Check for continuity between fuel pump 5P connector terminal No. 5 and body ground.
    Fig 11: Checking For Continuity Between Fuel Pump 5P Connector Terminal No. 5 And Body Ground
    G01399437Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES:  Replace PGM-FI main relay 2. Also replace the No. 17 FUEL PUMP (15A) fuse.

    NO:  Check the fuel pump, and replace it if necessary. Also replace the No. 17 FUEL PUMP (15A) fuse.

  34. Disconnect ECM connector E (31P).
  35. Turn the ignition switch ON (II).
  36. Measure voltage between ECM connector terminal E9 and body ground.
    Fig 12: Measuring Voltage Between ECM Connector Terminal E9 And Body Ground
    G01399438Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES:  Go to step 37.

    NO:  Repair open in the wire between the No. 17 FUEL PUMP (15A) fuse and the ECM (E9).

  37. Measure voltage between ECM connector terminal E7 and body ground.
    Fig 13: Measuring Voltage Between ECM Connector Terminal E7 And Body Ground
    G01399439Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES:  Go to step  42.

    NO:  Go to step 38.

  38. Turn the ignition switch OFF.
  39. Remove PGM-FI main relay 1 (A).
    Fig 14: Removing PGM-FI Main Relay 1
    G01399440Courtesy of AMERICAN HONDA MOTOR CO., INC.
  40. Measure voltage between PGM-FI main relay 1 4P connector terminal No. 4 and body ground.
    Fig 15: Measuring Voltage Between PGM-FI Main Relay 1 4P Connector Terminal No. 4 And Body Ground
    G01399441Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES:  Go to step 41.

    NO:  Repair open in the wire between the No. 6 ECU (ECM) (15A) fuse and PGM-FI main relay 1.

  41. Check for continuity between PGM-FI main relay 1 4P connector terminal No. 3 and ECM connector terminal E7.
    Fig 16: Checking For Continuity Between PGM-FI Main Relay 1 4P Connector Terminal No. 3 And ECM Connector Terminal E7
    G01399442Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES:  Test PGM-FI main relay 1 (see POWER RELAY TEST ). If the relay is OK, update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck (see ECM UPDATING AND SUBSTITUTION FOR TESTING ). If the symptom/indication goes away with a known-good ECM, replace the original ECM.

    NO:  Repair open in the wire between PGM-FI main relay 1 and the ECM (E7).

  42. Reconnect ECM connector E (31P).
  43. Turn the ignition switch ON (II).
  44. Measure voltage between body ground and ECM connector terminals A2 and A3 individually.
    Fig 17: Measuring Voltage Between Body Ground And ECM Connector Terminals A2 And A3 Individually
    G01399443Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES:  Go to step  51.

    NO:  Go to step 45.

  45. Turn the ignition switch OFF.
  46. Remove PGM-FI main relay 1 (A).
    Fig 18: Removing PGM-FI Main Relay 1
    G01399444Courtesy of AMERICAN HONDA MOTOR CO., INC.
  47. Turn the ignition switch ON (II).
  48. Measure voltage between PGM-FI main relay 1 4P connector terminal No. 2 and body ground.
    Fig 19: Measuring Voltage Between PGM-FI Main Relay 1 4P Connector Terminal No. 2 And Body Ground
    G01399445Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES:  Go to step 49.

    NO:  Repair open in the wire between the No. 6 ECU (ECM) (15A) fuse and PGM-FI main relay 1.

  49. Turn the ignition switch OFF.
  50. Check for continuity between PGM-FI main relay 4P connector terminal No. 1 and ECM connector terminals A2 and A3 individually.
    Fig 20: Checking For Continuity Between PGM-FI Main Relay 4P Connector Terminal No. 1 And ECM Connector Terminals A2 And A3 Individually
    G01399446Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES:  Replace PGM-FI main relay 1.

    NO:  Repair open in the wire between PGM-FI main relay 1 and the ECM (A2, A3).

  51. Measure voltage between body ground and ECM connector terminals A4, A5, A23, and A24 individually.
    Fig 21: Measuring Voltage Between Body Ground And ECM Connector Terminals A4, A5, A23, And A24 Individually
    G01399447Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there more than 1.0 V? 

    YES:  Go to step 52.

    NO:  Repair open in the wire(s) that had more than 1.0 V between G101 and the ECM (A4, A5, A23, A24).

  52. Measure voltage between body ground and ECM connector terminal A21.
    Fig 22: Measuring Voltage Between Body Ground And ECM Connector Terminal A21
    G01399448Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there about 5 V? 

    YES:  Go to step  60.

    NO:  Go to step 53.

  53. Turn the ignition switch OFF.
  54. Disconnect the manifold absolute pressure (MAP) sensor 3P connector.
  55. Turn the ignition switch ON (II).
  56. Measure voltage between body ground and ECM connector terminal A21.
    Fig 23: Measuring Voltage Between Body Ground And ECM Connector Terminal A21
    G01399449Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there about 5 V? 

    YES:  Replace the MAP sensor.

    NO:  Go to step 57.

  57. Turn the ignition switch OFF.
  58. Disconnect ECM connector A (31P).
  59. Check for continuity between ECM connector terminal A21 and body ground.
    Fig 24: Checking For Continuity Between ECM Connector Terminal A21 And Body Ground
    G01399450Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES:  Repair short in the wire between the ECM (A21) and the MAP sensor.

    NO:  Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck (see ECM UPDATING AND SUBSTITUTION FOR TESTING ). If the symptom/indication goes away with a known-good ECM, replace the original ECM.

  60. Measure voltage between body ground and ECM connector terminal A20.
    Fig 25: Measuring Voltage Between Body Ground And ECM Connector Terminal A20
    G01399451Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there about 5 V? 

    YES:  Go to step  68.

    NO:  Go to step 61.

  61. Turn the ignition switch OFF.
  62. Disconnect the throttle position (TP) sensor 3P connector.
  63. Turn the ignition switch ON (II).
  64. Measure voltage between body ground and ECM connector terminal A20.
    Fig 26: Measuring Voltage Between Body Ground And ECM Connector Terminal A20
    G01399452Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there about 5 V? 

    YES:  Replace the throttle body (the TP sensor is not available separately) (see THROTTLE BODY REMOVAL/INSTALLATION ).

    NO:  Go to step 65.

  65. Turn the ignition switch OFF.
  66. Disconnect ECM connector A (31P).
  67. Check for continuity between ECM connector terminal A20 and body ground.
    Fig 27: Checking For Continuity Between ECM Connector Terminal A20 And Body Ground
    G01399453Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES:  Repair short in the wire between the ECM (A20) and the TP sensor, or repair short in the wire between the ECM (A8) and the knock sensor.

    NO:  Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck (see ECM UPDATING AND SUBSTITUTION FOR TESTING ). If the symptom/indication goes away with a known-good ECM, replace the original ECM.

  68. Measure voltage between body ground and ECM connector terminal E5.
    Fig 28: Measuring Voltage Between Body Ground And ECM Connector Terminal E5
    G01399454Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there about 5 V? 

    YES:  Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck (see ECM UPDATING AND SUBSTITUTION FOR TESTING ). If the symptom/indication goes away with a known-good ECM, replace the original ECM.

    NO:  Go to step 69.

  69. Turn the ignition switch OFF.
  70. Disconnect the fuel tank pressure (FTP) sensor 3P connector.
  71. Turn the ignition switch ON (II).
  72. Measure voltage between body ground and ECM connector terminal E5.
    Fig 29: Measuring Voltage Between Body Ground And ECM Connector Terminal E5
    G01399455Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there about 5 V? 

    YES:  Replace the FTP sensor.

    NO:  Go to step 73.

  73. Turn the ignition switch OFF.
  74. Disconnect ECM connector E (31P).
  75. Check for continuity between ECM connector terminal E5 and body ground.
    Fig 30: Checking For Continuity Between ECM Connector Terminal E5 And Body Ground
    G01399456Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES:  Repair short in the wire between the ECM (E5) and the FTP sensor.

    NO:  Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck (see ECM UPDATING AND SUBSTITUTION FOR TESTING ). If the symptom/indication goes away with a known-good ECM, replace the original ECM.

  76. Turn the ignition switch OFF.
  77. Turn the ignition switch ON (II).
  78. Measure voltage between ECM connector terminal E29 and body ground.
    Fig 31: Measuring Voltage Between ECM Connector Terminal E29 And Body Ground
    G01399457Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there about 5 V (or battery voltage)? 

    YES:  Go to step  82.

    NO:  Go to step 79.

  79. Turn the ignition switch OFF.
  80. Disconnect ECM connector E (31P).
  81. Check for continuity between ECM connector terminal E29 and body ground.
    Fig 32: Checking For Continuity Between ECM Connector Terminal E29 And Body Ground
    G01399458Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES:  Repair short in the wire between the data link connector (DLC) and the ECM (E29).

    NO:  Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck (see ECM UPDATING AND SUBSTITUTION FOR TESTING ). If the symptom/indication goes away with a known-good ECM, replace the original ECM.

  82. Turn the ignition switch OFF.
  83. Disconnect ECM connector E (31P).
  84. Turn the ignition switch ON (II).

    Does the MIL stay on? 

    YES:  Repair short in the wire between the gauge assembly and the ECM (E31). If the wire is OK, replace the gauge assembly.

    NO:  Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck (see ECM UPDATING AND SUBSTITUTION FOR TESTING ). If the symptom/indication goes away with a known-good ECM, replace the original ECM.

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