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Home >> Honda >> 2021 >> Civic Touring >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> Network Communication - Testing & Troubleshooting >> Troubleshooting >> F-CAN Circuit Troubleshooting (L15B7/L15BA/L15BY: Without CAN gateway)

F-CAN Circuit Troubleshooting (L15B7/L15BA/L15BY: Without CAN gateway)

  1. F-CAN circuit resistance check

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Jump the SCS line with the HDS, and wait more than 1 minute.

    -3. Disconnect the following connector.

    PCM connector A (50P)

    -4. Measure the resistance between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
      PCM connector A (50P): disconnected
    Test point 1 PCM connector A (50P) No. 36
    Test point 2 PCM connector A (50P) No. 37

    Is there about 85-107 Ω (CVT), 88-111 Ω (M/T)?

    YES 

    Go to step 16.

    NO 

    Go to step 2.

  2. Shorted wire check (F-CAN_H line to F-CAN_L line):

    Disconnect the following connectors.

    • Gauge control module connector A (32P)
    • VSA modulator-control unit 46P connector
    • EPS control unit connector B (6P)
    • Body control module connector B (36P)
    • SRS unit connector A (39P)
    • Audio unit connector E (16P) (display audio type, without navigation)
    • Audio-navigation unit connector E (16P) (with navigation)
    • TCM 50P connector (CVT)

    -2. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Gauge control module connector A (32P): disconnected
    VSA modulator-control unit 46P connector: disconnected
    EPS control unit connector B (6P): disconnected
    Body control module connector B (36P): disconnected
    SRS unit connector A (39P): disconnected
    Audio unit connector E (16P) (display audio type, without navigation): disconnected
    Audio-navigation unit connector E (16P) (with navigation): disconnected
    TCM 50P connector (CVT): disconnected
    Test point 1 PCM connector A (50P) No. 36
    Test point 2 PCM connector A (50P) No. 37

    Is there continuity?

    YES 

    Repair a short in the F-CAN_H wire to F-CAN_L wire between the PCM terminals A36 and A37.

    NO 

    The F-CAN_H and F-CAN_L wires are not shorted. Go to step 3.

  3. Open wire check (F-CAN_H line) 1

    -1. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Gauge control module connector A (32P): disconnected
    VSA modulator-control unit 46P connector: disconnected
    EPS control unit connector B (6P): disconnected
    Body control module connector B (36P): disconnected
    SRS unit connector A (39P): disconnected
    Audio unit connector E (16P) (display audio type, without navigation): disconnected
    Audio-navigation unit connector E (16P) (with navigation): disconnected
    TCM 50P connector (CVT): disconnected
    Test point 1 Gauge control module connector A (32P) No. 19
    Test point 2 PCM connector A (50P) No. 37

    Is there continuity?

    YES 

    The F-CAN_H wire is not open. Go to step 4.

    NO 

    Repair an open in the F-CAN_H wire between the PCM (A37) and the gauge control module.

  4. Open wire check (F-CAN_H line) 2

    -1. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Gauge control module connector A (32P): disconnected
    VSA modulator-control unit 46P connector: disconnected
    EPS control unit connector B (6P): disconnected
    Body control module connector B (36P): disconnected
    SRS unit connector A (39P): disconnected
    Audio unit connector E (16P) (display audio type, without navigation): disconnected
    Audio-navigation unit connector E (16P) (with navigation): disconnected
    TCM 50P connector (CVT): disconnected
    Test point 1 VSA modulator-control unit 46P connector No. 20
    Test point 2 PCM connector A (50P) No. 37

    Is there continuity?

    YES 

    The F-CAN_H wire is not open. Go to step 5.

    NO 

    Repair an open in the F-CAN_H wire between the PCM (A37) and the VSA modulator-control unit.

  5. Open wire check (F-CAN_H line) 3

    -1. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Gauge control module connector A (32P): disconnected
    VSA modulator-control unit 46P connector: disconnected
    EPS control unit connector B (6P): disconnected
    Body control module connector B (36P): disconnected
    SRS unit connector A (39P): disconnected
    Audio unit connector E (16P) (display audio type, without navigation): disconnected
    Audio-navigation unit connector E (16P) (with navigation): disconnected
    TCM 50P connector (CVT): disconnected
    Test point 1 EPS control unit connector B (6P) No. 3
    Test point 2 PCM connector A (50P) No. 37

    Is there continuity?

    YES 

    The F-CAN_H wire is not open. Go to step 6.

    NO 

    Repair an open in the F-CAN_H wire between the PCM (A37) and the EPS control unit.

  6. Open wire check (F-CAN_H line) 4

    -1. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Gauge control module connector A (32P): disconnected
    VSA modulator-control unit 46P connector: disconnected
    EPS control unit connector B (6P): disconnected
    Body control module connector B (36P): disconnected
    SRS unit connector A (39P): disconnected
    Audio unit connector E (16P) (display audio type, without navigation): disconnected
    Audio-navigation unit connector E (16P) (with navigation): disconnected
    TCM 50P connector (CVT): disconnected
    Test point 1 SRS unit connector A (39P) No. 34
    Test point 2 PCM connector A (50P) No. 37

    Is there continuity?

    YES (CVT)

    The F-CAN_H wire is not open. Go to step 7.

    YES (M/T)

    The F-CAN_H wire is not open. Go to step 8.

    NO 

    Repair an open in the F-CAN_H wire between the PCM (A37) and the SRS unit.

  7. Open wire check (F-CAN_H line) 5

    -1. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Gauge control module connector A (32P): disconnected
    VSA modulator-control unit 46P connector: disconnected
    EPS control unit connector B (6P): disconnected
    Body control module connector B (36P): disconnected
    SRS unit connector A (39P): disconnected
    Audio unit connector E (16P) (display audio type, without navigation): disconnected
    Audio-navigation unit connector E (16P) (with navigation): disconnected
    TCM 50P connector: disconnected
    Test point 1 TCM 50P connector No. 3
    Test point 2 PCM connector A (50P) No. 37

    Is there continuity?

    YES 

    The F-CAN_H wire is not open. Go to step 8.

    NO 

    Repair an open in the F-CAN_H wire between the PCM (A37) and the TCM.

  8. Open wire check (F-CAN_H line) 6

    -1. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Gauge control module connector A (32P): disconnected
    VSA modulator-control unit 46P connector: disconnected
    EPS control unit connector B (6P): disconnected
    Body control module connector B (36P): disconnected
    SRS unit connector A (39P): disconnected
    Audio unit connector E (16P) (display audio type, without navigation): disconnected
    Audio-navigation unit connector E (16P) (with navigation): disconnected
    TCM 50P connector (CVT): disconnected
    Test point 1 Body control module connector B (36P) No. 22
    Test point 2 PCM connector A (50P) No. 37

    Is there continuity?

    YES 

    The F-CAN_H wire is not open. Go to step 9.

    NO 

    Repair an open in the F-CAN_H wire between the PCM (A37) and the body control module.

  9. Open wire check (F-CAN_L line) 1

    -1. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Gauge control module connector A (32P): disconnected
    VSA modulator-control unit 46P connector: disconnected
    EPS control unit connector B (6P): disconnected
    Body control module connector B (36P): disconnected
    SRS unit connector A (39P): disconnected
    Audio unit connector E (16P) (display audio type, without navigation): disconnected
    Audio-navigation unit connector E (16P) (with navigation): disconnected
    TCM 50P connector (CVT): disconnected: disconnected
    Test point 1 Gauge control module connector A (32P) No. 20
    Test point 2 PCM connector A (50P) No. 36

    Is there continuity?

    YES 

    The F-CAN_L wire is not open. Go to step 10.

    NO 

    Repair an open in the F-CAN_L wire between the PCM (A36) and the gauge control module.

  10. Open wire check (F-CAN_L line) 2

    -1. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Gauge control module connector A (32P): disconnected
    VSA modulator-control unit 46P connector: disconnected
    EPS control unit connector B (6P): disconnected
    Body control module connector B (36P): disconnected
    SRS unit connector A (39P): disconnected
    Audio unit connector E (16P) (display audio type, without navigation): disconnected
    Audio-navigation unit connector E (16P) (with navigation): disconnected
    TCM 50P connector (CVT): disconnected
    Test point 1 VSA modulator-control unit 46P connector No. 21
    Test point 2 PCM connector A (50P) No. 36

    Is there continuity?

    YES 

    The F-CAN_L wire is not open. Go to step 11.

    NO 

    Repair an open in the F-CAN_L wire between the PCM (A36) and the VSA modulator-control unit.

  11. Open wire check (F-CAN_L line) 3

    -1. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Gauge control module connector A (32P): disconnected
    VSA modulator-control unit 46P connector: disconnected
    EPS control unit connector B (6P): disconnected
    Body control module connector B (36P): disconnected
    SRS unit connector A (39P): disconnected
    Audio unit connector E (16P) (display audio type, without navigation): disconnected
    Audio-navigation unit connector E (16P) (with navigation): disconnected
    TCM 50P connector (CVT): disconnected
    Test point 1 EPS control unit connector B (6P) No. 1
    Test point 2 PCM connector A (50P) No. 36

    Is there continuity?

    YES 

    The F-CAN_L wire is not open. Go to step 12.

    NO 

    Repair an open in the F-CAN_L wire between the PCM (A36) and the EPS control unit.

  12. Open wire check (F-CAN_L line) 4

    -1. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Gauge control module connector A (32P): disconnected
    VSA modulator-control unit 46P connector: disconnected
    EPS control unit connector B (6P): disconnected
    Body control module connector B (36P): disconnected
    SRS unit connector A (39P): disconnected
    Audio unit connector E (16P) (display audio type, without navigation): disconnected
    Audio-navigation unit connector E (16P) (with navigation): disconnected
    TCM 50P connector (CVT): disconnected
    Test point 1 SRS unit connector A (39P) No. 35
    Test point 2 PCM connector A (50P) No. 36

    Is there continuity?

    YES (CVT)

    The F-CAN_L wire is not open. Go to step 13.

    YES (M/T)

    The F-CAN_L wire is not open. Go to step 14.

    NO 

    Repair an open in the F-CAN_L wire between the PCM (A36) and the SRS unit.

  13. Open wire check (F-CAN_L line) 5

    -1. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Gauge control module connector A (32P): disconnected
    VSA modulator-control unit 46P connector: disconnected
    EPS control unit connector B (6P): disconnected
    Body control module connector B (36P): disconnected
    SRS unit connector A (39P): disconnected
    Audio unit connector E (16P) (display audio type, without navigation): disconnected
    Audio-navigation unit connector E (16P) (with navigation): disconnected
    TCM 50P connector: disconnected
    Test point 1 TCM 50P connector No. 11
    Test point 2 PCM connector A (50P) No. 36

    Is there continuity?

    YES 

    The F-CAN_L wire is not open. Go to step 14.

    NO 

    Repair an open in the F-CAN_L wire between the PCM (A36) and the TCM.

  14. Open wire check (F-CAN_L line) 6

    -1. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Gauge control module connector A (32P): disconnected
    VSA modulator-control unit 46P connector: disconnected
    EPS control unit connector B (6P): disconnected
    Body control module connector B (36P): disconnected
    SRS unit connector A (39P): disconnected
    Audio unit connector E (16P) (display audio type, without navigation): disconnected
    Audio-navigation unit connector E (16P) (with navigation): disconnected
    TCM 50P connector (CVT): disconnected
    Test point 1 Body control module connector B (36P) No. 23
    Test point 2 PCM connector A (50P) No. 36

    Is there continuity?

    YES 

    The F-CAN_L wire is not open. Go to step 15.

    NO 

    Repair an open in the F-CAN_L wire between the PCM (A36) and the body control module.

  15. VSA modulator-control unit internal resistance check

    -1. Reconnect VSA modulator-control unit 46P connector.

    -2. Measure the resistance between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Gauge control module connector A (32P): disconnected
    EPS control unit connector B (6P): disconnected
    Body control module connector B (36P): disconnected
    SRS unit connector A (39P): disconnected
    Audio unit connector E (16P) (display audio type, without navigation): disconnected
    Audio-navigation unit connector E (16P) (with navigation): disconnected
    TCM 50P connector (CVT): disconnected
    Test point 1 PCM connector A (50P) No. 36
    Test point 2 PCM connector A (50P) No. 37

    Is there about 112-136 Ω ?

    YES 

    Go to step 16.

    NO 

    Replace the VSA modulator-control unit .

  16. Shorted wire check (F-CAN_H line):

    Disconnect the following connectors.

    • Gauge control module connector A (32P)
    • VSA modulator-control unit 46P connector
    • EPS control unit connector B (6P)
    • Body control module connector B (36P)
    • SRS unit connector A (39P)
    • Audio unit connector E (16P) (display audio type, without navigation)
    • Audio-navigation unit connector E (16P) (with navigation)
    • TCM 50P connector (CVT)

    -2. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Gauge control module connector A (32P): disconnected
    VSA modulator-control unit 46P connector: disconnected
    EPS control unit connector B (6P): disconnected
    Body control module connector B (36P): disconnected
    SRS unit connector A (39P): disconnected
    Audio unit connector E (16P) (display audio type, without navigation): disconnected
    Audio-navigation unit connector E (16P) (with navigation): disconnected
    TCM 50P connector (CVT): disconnected
    Test point 1 PCM connector A (50P) No. 37
    Test point 2 Body ground

    Is there continuity?

    YES 

    Repair a short in the F-CAN_H wire between the PCM (A37) and the gauge control module, the VSA modulator-control unit, the EPS control unit, the body control module, the SRS unit, the audio unit, the audio-navigation unit, the TCM, or the DLC.

    NO 

    The F-CAN_H wire is OK. Go to step 17.

  17. Shorted wire check (F-CAN_L line)

    -1. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    PCM connector A (50P): disconnected
    Gauge control module connector A (32P): disconnected
    VSA modulator-control unit 46P connector: disconnected
    EPS control unit connector B (6P): disconnected
    Body control module connector B (36P): disconnected
    SRS unit connector A (39P): disconnected
    Audio unit connector E (16P) (display audio type, without navigation): disconnected
    Audio-navigation unit connector E (16P) (with navigation): disconnected
    TCM 50P connector (CVT): disconnected
    Test point 1 PCM connector A (50P) No. 36
    Test point 2 Body ground

    Is there continuity?

    YES 

    Repair a short in the F-CAN_L wire between the PCM (A36) and the gauge control module, the VSA modulator-control unit, the EPS control unit, the body control module, the SRS unit, the audio unit, the audio-navigation unit, the TCM, or the DLC.

    NO 

    The F-CAN_L wire is OK. Go to step 18.

  18. Gauge control module check

    -1. Reconnect all connectors.

    -2. Connect the HDS to the DLC.

    -3. Disconnect the following connector.

    Gauge control module connector A (32P)

    -4. Turn the vehicle to the ON mode, and read the HDS.

    Does the HDS identify the vehicle?

    YES 

    Replace the gauge control module .

    NO 

    Reconnect gauge control module connector A (32P) with vehicle in OFF (LOCK) mode, then go to step 19.

  19. VSA modulator-control unit check

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Disconnect the following connector.

    VSA modulator-control unit 46P connector

    -3. Turn the vehicle to the ON mode, and read the HDS.

    Does the HDS identify the vehicle?

    YES 

    Replace the VSA modulator-control unit .

    NO (with navigation)

    Reconnect the VSA modulator-control unit 46P connector with vehicle in OFF (LOCK) mode, then go to step 21.

    NO (without display audio type)

    Reconnect the VSA modulator-control unit 46P connector with vehicle in OFF (LOCK) mode, then go to step 22.

    OK (display audio type, without navigation)

    Reconnect the VSA modulator-control unit 46P connector with vehicle in OFF (LOCK) mode, then go to step 20.

  20. Audio unit check

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Disconnect the following connector.

    Audio unit connector E (16P)

    -3. Turn the vehicle to the ON mode, and read the HDS.

    Does the HDS identify the vehicle?

    YES 

    Replace the audio unit .

    NO 

    Reconnect audio unit connector E (16P) with vehicle in OFF (LOCK) mode, then go to step 22.

  21. Audio-navigation unit check

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Disconnect the following connector.

    Audio-navigation unit connector E (16P)

    -3. Turn the vehicle to the ON mode, and read the HDS.

    Does the HDS identify the vehicle?

    YES 

    Replace the audio-navigation unit .

    NO 

    Reconnect audio-navigation unit connector E (16P) with vehicle in OFF (LOCK) mode, then go to step 22.

  22. EPS control unit check

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Disconnect the following connector.

    EPS control unit connector B (6P)

    -3. Turn the vehicle to the ON mode, and read the HDS.

    Does the HDS identify the vehicle?

    YES 

    Replace the EPS control unit .

    NO (CVT)

    Reconnect EPS control unit connector B (6P) with vehicle in OFF (LOCK) mode, then go to step 23.

    NO (M/T)

    Reconnect EPS control unit connector B (6P) with vehicle in OFF (LOCK) mode, then go to step 24.

  23. TCM check

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Disconnect the following connector.

    TCM 50P connector

    -3. Turn the vehicle to the ON mode, and read the HDS.

    Does the HDS identify the vehicle?

    YES 

    Replace the TCM .

    NO 

    Reconnect the TCM 50P connector with vehicle in OFF (LOCK) mode, then go to step 24.

  24. SRS unit check

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Do the 12 volt battery terminal disconnection procedure , and wait for at least 3 minutes.

    -3. Disconnect the following connector.

    SRS unit connector A (39P)

    -4. Do the 12 volt battery terminal reconnection procedure .

    -5. Turn the vehicle to the ON mode, and read the HDS.

    Does the HDS identify the vehicle?

    YES 

    Replace the SRS unit .

    NO