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DTC U12AA (A/T System (With CAN Gateway)) (2016 2017 2018)

DTC U12AA  : Lost Communication with Shifter

NOTE:

  • Before you troubleshoot, record all freeze data and any on-board snapshots, and review the General Troubleshooting Information .
  • According to the detected DTC (s), check for the power circuit and the ground circuit of the control unit which cannot communicate with the TCM.

DTC Description Confirmed DTC Pending DTC Freeze Frame
U12AA Lost Communication with Shifter      

DTC (A/T)

  1. Problem verification

    - 1. Turn the vehicle to the ON mode.

    - 2. Clear the DTC with the HDS.

    - 3. Check for Pending or Confirmed DTCs with the HDS.

    DTC Description Confirmed DTC Pending DTC Freeze Frame
    U12AA Lost Communication with Shifter      

    Is DTC U12AA indicated?

    YES 

    The failure is duplicated. Go to step 2.

    NO 

    Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the keyless access/TPMS 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.

  2. CAN gateway system DTC check

    - 1. Turn the vehicle to the ON mode.

    - 2. 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  
    U3000-49 CAN Gateway Internal Failure  

    Is DTC U0029-00, U0047-00, and/or U3000-49 indicated?

    YES 

    Go to the indicated DTC's troubleshooting in the CAN gateway system .

    NO 

    Go to step 3.

  3. F-CAN circuit communication check

    - 1. Select the FUNCTION TEST in the CAN gateway with the HDS, then select the F-CAN Bus Connected Unit Check.

    F-CAN Bus Connected Unit Check

    Which result is indicated?

    TCM (Bus A) is Not Available

    Go to step 4.

    TCM (Bus B) is Not Available

    Go to step 6.

    SBW SHIFTER (Bus A) is Not Available

    Go to step 8.

    SBW SHIFTER (Bus B) is Not Available

    Go to step 10.

    TCM and SBW SHIFTER are Detected

    Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals between the SBW shifter control module, the CAN gateway, and the TCM.

  4. Open wire check (F-CAN A_H line)

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

    - 2. Disconnect the following connectors.

    CAN gateway 24P connector
    TCM 58P connector

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

    Test condition Vehicle OFF (LOCK) mode
      CAN gateway 24P connector: disconnected
      TCM 58P connector: disconnected
    Test point 1 CAN gateway 24P connector No. 14
    Test point 2 TCM 58P connector No. 34
    GHH316346Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    The F-CAN A_H wire is OK. Go to step 5.

    NO 

    Repair an open in the F-CAN A_H wire between the CAN gateway and the TCM.

  5. Open wire check (F-CAN A_L line)

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

    Test condition Vehicle OFF (LOCK) mode
      CAN gateway 24P connector: disconnected
      TCM 58P connector: disconnected
    Test point 1 CAN gateway 24P connector No. 15
    Test point 2 TCM 58P connector No. 47
    GHH316347Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    The F-CAN A_L wire is OK. Update the TCM if it does not have the latest software , or substitute a known-good TCM , then recheck. If this DTC goes away and the TCM was updated, troubleshooting is complete. If this DTC goes away and the TCM was substituted, replace the original TCM .

    NO 

    Repair an open in the F-CAN A_L wire between the CAN gateway and the TCM.

  6. Open wire check (F-CAN B_H line)

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

    - 2. Disconnect the following connectors.

    CAN gateway 24P connector
    TCM 58P connector

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

    Test condition Vehicle OFF (LOCK) mode
      CAN gateway 24P connector: disconnected
      TCM 58P connector: disconnected
    Test point 1 CAN gateway 24P connector No. 11
    Test point 2 TCM 58P connector No. 7
    GHH316348Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    The F-CAN B_H wire is OK. Go to step 7.

    NO 

    Repair an open in the F-CAN B_H wire between the CAN gateway and the TCM.

  7. Open wire check (F-CAN B_L line)

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

    Test condition Vehicle OFF (LOCK) mode
      CAN gateway 24P connector: disconnected
      TCM 58P connector: disconnected
    Test point 1 CAN gateway 24P connector No. 10
    Test point 2 TCM 58P connector No. 20
    GHH316349Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    The F-CAN B_L wire is OK. Update the TCM if it does not have the latest software , or substitute a known-good TCM , then recheck. If this DTC goes away and the TCM was updated, troubleshooting is complete. If this DTC goes away and the TCM was substituted, replace the original TCM .

    NO 

    Repair an open in the F-CAN B_L wire between the CAN gateway and the TCM.

  8. Open wire check (F-CAN A_H line)

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

    - 2. Disconnect the following connectors.

    CAN gateway 24P connector
    SBW shifter control module 20P connector

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

    Test condition Vehicle OFF (LOCK) mode
      CAN gateway 24P connector: disconnected
      SBW shifter control module 20P connector: disconnected
    Test point 1 CAN gateway 24P connector No. 14
    Test point 2 SBW shifter control module 20P connector No. 5
    GHH316350Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    The F-CAN A_H wire is OK. Go to step 9.

    NO 

    Repair an open in the F-CAN A_H wire between the CAN gateway and the SBW shifter control module.

  9. Open wire check (F-CAN A_L line)

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

    Test condition Vehicle OFF (LOCK) mode
      CAN gateway 24P connector: disconnected
      SBW shifter control module 20P connector: disconnected
    Test point 1 CAN gateway 24P connector No. 15
    Test point 2 SBW shifter control module 20P connector No. 6
    GHH316351Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    The F-CAN A_L wire is OK. Faulty SBW shifter control module. Substitute a known-good SBW shifter assembly , then recheck. If this DTC goes away and the SBW shifter assembly was substituted, replace the original SBW shifter assembly .

    NO 

    Repair an open in the F-CAN A_L wire between the CAN gateway and the SBW shifter control module.

  10. Open wire check (F-CAN B_H line)

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

    - 2. Disconnect the following connectors.

    CAN gateway 24P connector
    SBW shifter control module 20P connector

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

    Test condition Vehicle OFF (LOCK) mode
      CAN gateway 24P connector: disconnected
      SBW shifter control module 20P connector: disconnected
    Test point 1 CAN gateway 24P connector No. 11
    Test point 2 SBW shifter control module 20P connector No. 9
    GHH316352Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    The F-CAN B_H wire is OK. Go to step 11.

    NO 

    Repair an open in the F-CAN B_H wire between the CAN gateway and the SBW shifter control module.

  11. Open wire check (F-CAN B_L line)

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

    Test condition Vehicle OFF (LOCK) mode
      CAN gateway 24P connector: disconnected
      SBW shifter control module 20P connector: disconnected
    Test point 1 CAN gateway 24P connector No. 10
    Test point 2 SBW shifter control module 20P connector No. 10
    GHH316353Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    The F-CAN B_L wire is OK. Faulty SBW shifter control module. Substitute a known-good SBW shifter assembly , then recheck. If this DTC goes away and the SBW shifter assembly was substituted, replace the original SBW shifter assembly .

    NO 

    Repair an open in the F-CAN B_L wire between the CAN gateway and the SBW shifter control module.

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