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HOMESERVICE MANUALSHONDA2008CIVIC SI, 4D SEDANREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT VARIANT/TRIMSECTION 85 (PGM-FI SYSTEM (R18A1 ENGINE))F-CAN CIRCUIT TROUBLESHOOTING
2008 Honda Civic Si, 4D Sedan

F-CAN Circuit Troubleshooting

2008 Honda Civic Si, 4D SedanSECTION F-CAN Circuit Troubleshooting
WARNING: This page is about a different variant/trim than selected.
  1. Turn the ignition switch to LOCK (0).
  2. Jump the SCS line with the HDS.
  3. Disconnect ECM/PCM connector A (44P), then disconnect the HDS.
  4. Measure the resistance between ECM/PCM connector terminals A36 and A37 using the appropriate reading from the table below.
    Fig 1: Measuring Resistance Between ECM/PCM Connector Terminals A36 And A37
    G06273040Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is the resistance about 88-121 Ω ? 

    YES  -Go to step 37.

    NO  -Go to step 5.

  5. Disconnect the gauge control module (tach) 36P connector (see TACHOMETER ).
  6. Disconnect the ABS modulator-control unit 25P connector (see ABS MODULATOR-CONTROL UNIT REMOVAL AND INSTALLATION ) or the VSA modulator-control unit 37P connector (see VSA MODULATOR-CONTROL UNIT REMOVAL AND INSTALLATION ) and the yaw rate/lateral acceleration sensor 4P connector (see YAW RATE-LATERAL ACCELERATION SENSOR REPLACEMENT ).
  7. Disconnect SRS unit connector A (28P) (see SRS UNIT REPLACEMENT ).
  8. With EPS: Disconnect EPS control unit connector D (28P) (see EPS CONTROL UNIT REMOVAL/INSTALLATION ).
  9. With TPMS: Disconnect the TPMS control unit 20P connector (see TPMS CONTROL UNIT REPLACEMENT ).
  10. Check for continuity between ECM/PCM connector terminals A36 and A37.
    Fig 2: Checking Continuity Between ECM/PCM Connector Terminals A36 And A37
    G06273041Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Repair short in the wires between ECM/PCM connector terminals A36 and A37.

    NO  -Go to step 11.

  11. Check for continuity between ECM/PCM connector terminal A36 and gauge control module (tach) 36P connector terminal No. 1.
    Fig 3: Connecting ECM/PCM Connector Terminal A36
    G00492619Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -

    • With VSA: Go to step 12.
    • Without VSA, but with EPS: Go to step 13.
    • Without VSA and EPS: Go to step 14.

    NO  -Repair open in the wire between the ECM/PCM (A36) and the gauge control module (tach).

  12. Check for continuity between ECM/PCM connector terminal A36 and VSA modulator-control unit 37P connector terminal No. 15.
    Fig 4: Checking Continuity Between Gauge Control Module 36P Connector Terminal 1 And Body Ground
    G00492620Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -

    • With EPS: Go to step 13.
    • Without VSA: Go to step  14.

    NO  -Repair open in the wire between the ECM/PCM (A36) and the VSA modulator-control unit.

  13. Check for continuity between ECM/PCM connector terminal A36 and EPS control unit connector D (28P) terminal No. 1.
    Fig 5: Checking Continuity Between VSA Modulator- Control Unit 37P Connector Terminal 15 And Body Ground
    G00492619Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step 14.

    NO  -Repair open in the wire between the ECM/PCM (A36) and the EPS control unit.

  14. Check for continuity between ECM/PCM connector terminal A37 and gauge control module (tach) 36P connector terminal No. 19.
    Fig 6: Checking Continuity Between EPS Control Unit Connector D (28P) Terminal 1 And Body Ground
    G00492622Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES- 

    • With VSA: Go to step 15.
    • Without VSA, but with EPS: Go to step 16.
    • Without VSA and EPS: Go to step 17.

    NO  -Repair open in the wire between the ECM/PCM (A37) and the gauge control module (tach).

  15. Check for continuity between ECM/PCM connector terminal A37 and VSA modulator-control unit 37P connector terminal No. 1.
    Fig 7: Checking Continuity Between ECM/PCM Connector Terminal A37 And VSA Modulator-Control Unit 37P Connector Terminal No. 1
    G00492623Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -

    • With EPS: Go to step 16.
    • Without EPS: Go to step 17.

      NO  -Repair open in the wire between the ECM/PCM (A37) and the VSA modulator-control unit.

  16. Check for continuity between ECM/PCM connector terminal A37 and EPS control unit connector D (28P) terminal No. 15.
    Fig 8: Checking Continuity Between ECM/PCM Connector Terminal A37 And Eps Control Unit Connector D (28P) Terminal No. 15.
    G00492624Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Go to step 17.

    NO  -Repair open in the wire between the ECM/PCM (A37) and the EPS control unit.

  17. Reconnect the gauge control module (tach) 36P connector.
  18. Measure the resistance between ECM/PCM connector terminals A36 and A37.
    Fig 9: Measuring Resistance Between ECM/PCM Connector Terminals A36 And A37
    G06273050Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there about 108-132 Ω ? 

    YES  -

    • With VSA: Go to step 19.
    • With VSA: Disconnect the gauge control module (tach) 36P connector (see TACHOMETER ), then go to step 22.

    NO  -Substitute a known-good gauge control module (tach) (see TACHOMETER ). If the HDS identifies the vehicle, replace the original gauge control module (tach) (see TACHOMETER ).

  19. Disconnect the gauge control module (tach) 36P connector.
  20. Reconnect the ABS modulator-control unit 25P connector.
  21. Measure the resistance between ECM/PCM connector terminals A36 and A37.
    Fig 10: Measuring Resistance Between ECM/PCM Connector Terminals A36 And A37
    G06273051Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there about 2.34-2.86 kΩ? 

    YES  -Go to step 28.

    NO  -Substitute a known-good ABS modulator-control unit (see ABS MODULATOR-CONTROL UNIT REMOVAL AND INSTALLATION ). If the HDS identifies the vehicle, replace the original ABS modulator-control unit (see ABS MODULATOR-CONTROL UNIT REMOVAL AND INSTALLATION ).

  22. Reconnect the VSA modulator-control unit 37P connector.
  23. Measure the resistance between ECM/PCM connector terminals A36 and A37.
    Fig 11: Measuring Resistance Between ECM/PCM Connector Terminals A36 And A37
    G06273052Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there about 2.34-2.86 kΩ? 

    YES  -Go to step 24.

    NO  -Substitute a known-good VSA modulator-control unit (see VSA MODULATOR-CONTROL UNIT REMOVAL AND INSTALLATION ), then reconnect ECM/PCM connector A(44P). If the HDS identifies the vehicle, replace the original VSA modulator-control unit (see VSA MODULATOR-CONTROL UNIT REMOVAL AND INSTALLATION ).

  24. Disconnect the VSA modulator-control unit 37P connector.
  25. Reconnect the yaw rate-lateral acceleration sensor 5P connector.
  26. Measure the resistance between ECM/PCM connector terminals A36 and A37.
    Fig 12: Measuring Resistance Between ECM/PCM Connector Terminals A36 And A37
    G06273053Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there about 2.34-2.86 kΩ? 

    YES  -Go to step 27.

    NO  -Substitute a known-good yaw rate-lateral acceleration sensor (see YAW RATE-LATERAL ACCELERATION SENSOR REPLACEMENT ), then reconnect ECM/PCM connector A (44P). If the HDS identifies the vehicle, replace the original yaw rate- lateral acceleration sensor (see YAW RATE-LATERAL ACCELERATION SENSOR REPLACEMENT ).

  27. Disconnect the yaw rate-lateral acceleration sensor 5P connector.
  28. Reconnect SRS unit connector A (28P).
  29. Measure the resistance between ECM/PCM connector terminals A36 and A37.
    Fig 13: Measuring Resistance Between ECM/PCM Connector Terminals A36 And A37
    G06273054Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there about 2.34-2.86 kΩ? 

    YES  -

    • With EPS: Go to step 30.
    • Without EPS, but with TPMS: Disconnect SRS unit connector A (28P), then go to step 34.
    • Without EPS and TPMS: Reconnect all connectors, then update the ECM/PCM if it does not have the latest software (see ECM/PCM UPDATE  ), or substitute a known-good ECM/PCM (see SUBSTITUTING THE ECM/PCM ), then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM (see ECM/PCM REPLACEMENT  ).

    NO  -Substitute a known-good SRS unit (see SUBSTITUTING THE ECM/PCMSRS UNIT REPLACEMENT ). If the HDS identifies the vehicle, replace the original SRS unit (see SRS UNIT REPLACEMENT ).

  30. Disconnect SRS unit connector A (28P).
  31. Reconnect EPS control unit connector D (28P).
  32. Measure the resistance between ECM/PCM connector terminals A36 and A37.
    Fig 14: Measuring Resistance Between ECM/PCM Connector Terminals A36 And A37
    G06273055Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there about 2.34-2.86 kΩ? 

    YES  -

    • With TPMS: Go to step 33.
    • Without TPMS: Reconnect all connectors, then update the ECM/PCM if it does not have the latest software (see ECM/PCM UPDATE  ), or substitute a known-good ECM/PCM (see SUBSTITUTING THE ECM/PCM ), then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM (see ECM/PCM REPLACEMENT  ).

    NO  -Substitute a known-good EPS control unit (see EPS CONTROL UNIT REMOVAL/INSTALLATION ). If the HDS identifies the vehicle, replace the original EPS control unit (see EPS CONTROL UNIT REMOVAL/INSTALLATION ).

  33. Disconnect EPS control unit connector D (28P).
  34. Reconnect the TPMS control unit 20P connector.
  35. Measure the resistance between ECM/PCM connector terminals A36 and A37.
    Fig 15: Measuring Resistance Between ECM/PCM Connector Terminals A36 And A37
    G06273056Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there about 2.34-2.86 kΩ? 

    YES  -Reconnect all connectors, then update the ECM/PCM if it does not have the latest software (see ECM/PCM UPDATE  ), or substitute a known-good ECM/PCM (see SUBSTITUTING THE ECM/PCM ), then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM (see ECM/PCM REPLACEMENT  ).

    NO  -Substitute a known-good TPMS control unit (see TPMS CONTROL UNIT REPLACEMENT ). If the HDS identifies the vehicle, replace the original TPMS control unit (see TPMS CONTROL UNIT REPLACEMENT ).

  36. Disconnect the gauge control module (tach) 36P connector (see TACHOMETER ).
  37. Disconnect the ABS modulator-control unit 25P connector (see ABS MODULATOR-CONTROL UNIT REMOVAL AND INSTALLATION ) or the VSA modulator-control unit 37P connector (see VSA MODULATOR-CONTROL UNIT REMOVAL AND INSTALLATION ) and the yaw rate/lateral acceleration sensor 5P connector (see YAW RATE-LATERAL ACCELERATION SENSOR REPLACEMENT ).
  38. Disconnect SRS unit connector A (28P) (see SRS UNIT REPLACEMENT ).
  39. With EPS: Disconnect EPS control unit connector D (28P) (see EPS CONTROL UNIT REMOVAL/INSTALLATION ).
  40. With TPMS: Disconnect the TPMS control unit 20P connector (see TPMS CONTROL UNIT REPLACEMENT ).
  41. Check for continuity between ECM/PCM connector terminal A36 and body ground.
    Fig 16: Checking Continuity Between ECM/PCM Connector Terminal A36 And Body Ground
    G06273057Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Repair short in the wire between ECM/PCM connector terminal A36 and the gauge control module (tach), the ABS modulator-control unit, the VSA modulator-control unit, the yaw rate/lateral acceleration sensor, the SRS unit, the EPS control unit, the TPMS control unit, or the DLC.

    NO  -Go to step 43.

  42. Check for continuity between ECM/PCM connector terminal A37 and body ground.
    Fig 17: Checking Continuity Between ECM/PCM Connector Terminal A37 And Body Ground
    G06273058Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Repair short in the wire between ECM/PCM connector terminal A37 and the gauge control module (tach), the ABS modulator-control unit, the VSA modulator-control unit, the yaw rate/lateral acceleration sensor, the SRS unit, the EPS control unit, the TPMS control unit, or the DLC.

    NO  -Go to step 44.

  43. Reconnect all connectors.
  44. Connect the HDS to the DLC (see GENERAL TROUBLESHOOTING INFORMATION ).
  45. Disconnect the gauge control module (tach) 36P connector.
  46. Turn the ignition switch to ON (II), and read the HDS.

    Does the HDS identify the vehicle? 

    YES  -Replace the gauge control module (tach) (see TACHOMETER ).

    NO  -

    • With VSA: Go to step 48.
    • With VSA: Turn the ignition switch to LOCK (0), then reconnect the gauge control module (tach) 36P connector, then go to step 52.
  47. Turn the ignition switch to LOCK (0).
  48. Reconnect the gauge control module (tach) 36P connector.
  49. Disconnect the ABS modulator-control unit 25P connector.
  50. Turn the ignition switch to ON (II), and read the HDS.

    Does the HDS identify the vehicle? 

    YES  -Replace the ABS modulator-control unit (see ABS MODULATOR-CONTROL UNIT REMOVAL AND INSTALLATION ).

    NO  -Turn the ignition switch to LOCK (0), and reconnect the ABS modulator-control unit 25P connector, then go to step 59.

  51. Disconnect the VSA modulator-control unit 37P connector.
  52. Turn the ignition switch to ON (II), and read the HDS.

    Does the HDS identify the vehicle? 

    YES  -Replace the VSA modulator-control unit (see VSA MODULATOR-CONTROL UNIT REMOVAL AND INSTALLATION ).

    NO  -Go to step 53.

  53. Turn the ignition switch to LOCK (0).
  54. Reconnect the VSA modulator-control unit 37P connector.
  55. Disconnect yaw rate-lateral acceleration sensor 5P connector.
  56. Turn the ignition switch to ON (II), and read the HDS.

    Does the HDS identify the vehicle? 

    YES  -Replace the yaw rate-lateral acceleration sensor (see YAW RATE-LATERAL ACCELERATION SENSOR REPLACEMENT ).

    NO  -Go to step 58.

  57. Turn the ignition switch to LOCK (0).
  58. Reconnect the yaw rate-lateral acceleration sensor 5P connector.
  59. Disconnect SRS unit connector A (28P).
  60. Turn the ignition switch to ON (II), and read the HDS.

    Does the HDS identify the vehicle? 

    YES  -Replace the SRS unit (see SRS UNIT REPLACEMENT ).

    NO  -

    • With EPS: Go to step 61.
    • Without EPS, but with TPMS: Turn the ignition switch to LOCK (0), then reconnect SRS unit connector A (28P), and go to step 66.
    • Without EPS and TPMS: Reconnect all connectors, then update the ECM/PCM if it does not have the latest software (see ECM/PCM UPDATE  ), or substitute a known-good ECM/PCM (see SUBSTITUTING THE ECM/PCM ), then recheck. If the HDS identifies the vehicle and the ECM/PCM was updated, troubleshooting is complete. If the HDS identifies the vehicle and the ECM/PCM was substituted, (see ECM/PCM REPLACEMENT  ).
  61. Turn the ignition switch to LOCK (0).
  62. Reconnect SRS unit connector A (28P).
  63. Disconnect EPS control unit connector D (28P).
  64. Turn the ignition switch to ON (II), and read the HDS.

    Does the HDS identify the vehicle? 

    YES  -Replace the EPS control unit (see EPS CONTROL UNIT REMOVAL/INSTALLATION ).

    NO  -

    • With TPMS: Go to step 66.
    • Without TPMS: Reconnect all connectors, then update the ECM/PCM if it does not have the latest software (see ECM/PCM UPDATE  ), or substitute a known-good ECM/PCM (see SUBSTITUTING THE ECM/PCM ), then recheck. If the HDS identifies the vehicle and the ECM/PCM was updated, troubleshooting is complete. If the HDS identifies the vehicle and the ECM/PCM was substituted, (see ECM/PCM REPLACEMENT  ).
  65. Turn the ignition switch to LOCK (0).
  66. Disconnect the TPMS control unit 20P connector.
  67. Turn the ignition switch to ON (II), and read the HDS.

    Does the HDS identify the vehicle? 

    YES  -Replace the TPMS control unit (see TPMS CONTROL UNIT REPLACEMENT ).

    NO  -Reconnect all connectors, then Update the ECM/PCM if it does not have the latest software (see ECM/PCM UPDATE  ), or substitute a known-good ECM/PCM (see SUBSTITUTING THE ECM/PCM ), then recheck. If the HDS identifies the vehicle and the ECM/PCM was updated, troubleshooting is complete. If the HDS identifies the vehicle and the ECM/PCM was substituted, (see ECM/PCM REPLACEMENT  ).

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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.