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DTC U0122: F-CAN Malfunction (PCM-VSA Modulator-Control Unit) (PGM-FI System) (2015)

NOTE:  Before You Troubleshoot, Review The General Troubleshooting Information - Refer To: How To Troubleshoot The Fuel And Emissions Systems (2014-15) .

DTC Description Confirmed DTC Pending DTC Freeze Frame
U0122 F-CAN Malfunction (PCM-VSA Modulator-Control Unit)      

DTC (PGM-FI)

  1. CAN Gateway System DTC Check

    -1. Check For CAN Gateway System DTCs With The HDS.

    DTC Description DTC
    U0029-00 CAN Gateway F-CAN Ch A Bus Off  
    U0047-00 CAN Gateway F-CAN Ch B Bus Off  
    U0056-00 CAN Gateway F-CAN Ch C Bus Off  
    U3000-49 CAN Gateway Internal Failure  

    DTC (CAN Gateway)

    Is DTC U0029-00, U0047-00, U0056-00, And/Or U3000-49 Indicated?

    Yes 

    Go To The Troubleshooting For CAN Gateway System DTC(s). - Refer To: Communication Systems DTC Troubleshooting Index (2015)

    No 

    Go To Step 2.

  2. F-CAN Circuit Communication Check

    -1. Select The Function Test In The CAN Gateway With The HDS, Then Select The F-CAN Bus Connected Units Check.

    Which Result Is Indicated?

    PCM (Bus A) Is Not Available

    Go To Step 3.

    PCM (Bus B) Is Not Available

    Go To Step 4.

    ABS/VSA (Bus B) Is Not Available

    Go To Step 5.

    ABS/VSA (Bus C) Is Not Available

    Go To Step 6.

    PCM And ABS/VSA Are Detected

    Intermittent Failure, The System Is OK At This Time. Check For Poor Connections Or Loose Terminals At The VSA Modulator-Control Unit, The CAN Gateway, And The PCM. If The Freeze Data/On-Board Snapshot Of This DTC Is Recorded, Try To Reproduce The Failure Under The Same Conditions With The Freeze Data/On-Board Snapshot.

  3. Open Wire Check (F-CAN A_L, F-CAN A_H Lines)

    -1. Jump The SCS Line With The HDS.

    - 2. Turn The Vehicle To The Off (Lock) Mode.

    - 3. Disconnect The Following Connectors.

    CAN Gateway 24P Connector - Refer To: CAN Gateway Removal And Installation (2014-15)
    PCM Connector A (51P) - Refer To: How To Troubleshoot The Fuel And Emissions Systems (2014-15)

    - 4. Check For Continuity Between Test Points 1 And 2.

    Test Condition Vehicle Off (Lock) Mode
      CAN Gateway 24P Connector: Disconnected
      PCM Connector A (51P): Disconnected
    Test Circuit F-CAN A_L
    Test Point 1 CAN Gateway 24P Connector No. 15 (Red)
    Test Point 2 PCM Connector A (51P) No. 4 (Red)
    Test Circuit F-CAN A_H
    Test Point 1 CAN Gateway 24P Connector No. 14 (Wht)
    Test Point 2 PCM Connector A (51P) No. 3 (Wht)
    GHH258700Courtesy of HONDA, U.S.A., INC.

    Is There Continuity?

    Yes 

    The F-CAN A_L And F-CAN A_H Wires Are OK. Check For Poor Connections Or Loose Terminals At The CAN Gateway And The PCM. Update The PCM If It Does Not Have The Latest Software, Or Substitute A Known-Good PCM - Refer To: PCM Removal And Installation (2014-15) , Then Recheck. If The DTC U0112 Goes Away And The PCM Was Updated, Troubleshooting Is Complete. If The DTC U0112 Goes Away And The PCM Was Substituted, Replace The Original PCM - Refer To: PCM Removal And Installation (2014-15) .

    No 

    Repair An Open In The F-CAN A_L Or F-CAN A_H Wire Between The PCM (A3, A4) And The CAN Gateway.

  4. Open Wire Check (F-CAN B_L, F-CAN B_H Lines)

    -1. Jump The SCS Line With The HDS.

    - 2. Turn The Vehicle To The Off (Lock) Mode.

    - 3. Disconnect The Following Connectors.

    CAN Gateway 24P Connector - Refer To: CAN Gateway Removal And Installation (2014-15)
    PCM Connector A (51P) - Refer To: How To Troubleshoot The Fuel And Emissions Systems (2014-15)

    - 4. Check For Continuity Between Test Points 1 And 2.

    Test Condition Vehicle Off (Lock) Mode
      CAN Gateway 24P Connector: Disconnected
      PCM Connector A (51P): Disconnected
    Test Circuit F-CAN B_L
    Test Point 1 CAN Gateway 24P Connector No. 10 (Lt Grn)
    Test Point 2 PCM Connector A (51P) No. 6 (Lt Grn)
    Test Circuit F-CAN B_H
    Test Point 1 CAN Gateway 24P Connector No. 11 (Grn)
    Test Point 2 PCM Connector A (51P) No. 5 (Lt Blu)
    GHH258701Courtesy of HONDA, U.S.A., INC.

    Is There Continuity?

    Yes 

    The F-CAN B_L And F-CAN B_H Wires Are OK. Check For Poor Connections Or Loose Terminals At The CAN Gateway And The PCM. Update The PCM If It Does Not Have The Latest Software, Or Substitute A Known-Good PCM - Refer To: PCM Removal And Installation (2014-15) , Then Recheck. If The DTC U0122 Goes Away And The PCM Was Updated, Troubleshooting Is Complete. If The DTC U0122 Goes Away And The PCM Was Substituted, Replace The Original PCM - Refer To: PCM Removal And Installation (2014-15) .

    No 

    Repair An Open In The F-CAN B_L Or F-CAN B_H Wire Between The PCM (A5, A6) And The CAN Gateway.

  5. Open Wire Check (F-CAN B_L, F-CAN B_H Lines)

    -1. Turn The Vehicle To The Off (Lock) Mode.

    - 2. Disconnect The Following Connectors.

    CAN Gateway 24P Connector - Refer To: CAN Gateway Removal And Installation (2014-15)
    VSA Modulator-Control Unit 21P Connector

    - 3. Check For Continuity Between Test Points 1 And 2.

    Test Condition Vehicle Off (Lock) Mode
      CAN Gateway 24P Connector: Disconnected
      VSA Modulator-Control Unit 21P Connector: Disconnected
    Test Circuit F-CAN B_L
    Test Point 1 CAN Gateway 24P Connector No. 10 (Lt Grn)
    Test Point 2 VSA Modulator-Control Unit 21P Connector No. 15 (Lt Grn)
    Test Circuit F-CAN B_H
    Test Point 1 CAN Gateway 24P Connector No. 11 (Grn)
    Test Point 2 VSA Modulator-Control Unit 21P Connector No. 8 (Lt Blu)
    GHH258702Courtesy of HONDA, U.S.A., INC.

    Is There Continuity?

    Yes 

    The F-CAN B_L And F-CAN B_H Wires Are OK. Check For Poor Connections Or Loose Terminals At The CAN Gateway And The VSA Modulator-Control Unit. Update The VSA Modulator-Control Unit If It Does Not Have The Latest Software, Then Recheck. If The DTC U0122 Goes Away And The VSA Modulator-Control Unit Was Updated, Troubleshooting Is Complete. If The DTC U0122 Goes Away And The VSA Modulator-Control Unit Was Substituted, Replace The Original VSA Modulator-Control Unit .

    No 

    Repair An Open In The F-CAN B_L Or F-CAN B_H Wire Between The CAN Gateway And The VSA Modulator-Control Unit.

  6. Open Wire Check (F-CAN C_L, F-CAN C_H Lines)

    -1. Turn The Vehicle To The Off (Lock) Mode.

    - 2. Disconnect The Following Connectors.

    CAN Gateway 24P Connector - Refer To: CAN Gateway Removal And Installation (2014-15)
    VSA Modulator-Control Unit 21P Connector

    - 3. Check For Continuity Between Test Points 1 And 2.

    Test Condition Vehicle Off (Lock) Mode
      CAN Gateway 24P Connector: Disconnected
      VSA Modulator-Control Unit 21P Connector: Disconnected
    Test Circuit F-CAN C_L
    Test Point 1 CAN Gateway 24P Connector No. 8 (Pur)
    Test Point 2 VSA Modulator-Control Unit 21P Connector No. 16 (Pur)
    Test Circuit F-CAN C_H
    Test Point 1 CAN Gateway 24P Connector No. 9 (Tan)
    Test Point 2 VSA Modulator-Control Unit 21P Connector No. 9 (Orn)
    GHH258703Courtesy of HONDA, U.S.A., INC.

    Is There Continuity?

    Yes 

    The F-CAN C_L And F-CAN C_H Wires Are OK. Check For Poor Connections Or Loose Terminals At The CAN Gateway And The VSA Modulator-Control Unit. Update The VSA Modulator-Control Unit If It Does Not Have The Latest Software, Then Recheck. If The DTC U0122 Goes Away And The VSA Modulator-Control Unit Was Updated, Troubleshooting Is Complete. If The DTC U0122 Goes Away And The VSA Modulator-Control Unit Was Substituted, Replace The Original VSA Modulator-Control Unit .

    No 

    Repair An Open In The F-CAN C_L Or F-CAN C_H Wire Between The CAN Gateway And The VSA Modulator-Control Unit.

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