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Home >> Honda >> 2021 >> Accord Touring >> Repair and Diagnosis >> Accessories & Equipment >> Collision/Avoidance >> Parking Or Back-Up System - Diagnostics (Except Hybrid) >> DTC Troubleshooting >> DTC U0101, U0122, U0155 (Parking and Back-Up Sensor Control Unit)

DTC U0101, U0122, U0155 (Parking and Back-Up Sensor Control Unit)

DTC U0101  : Lost Communication with The PCM/TCM DTC U0122  : Lost Communication with The VSA Modulator-Control Unit DTC U0155  : Lost Communication with The Gauge Control Module

NOTE: 

DTC Description DTC
U0101 Lost communication with the PCM/TCM  
U0122 Lost communication with the VSA modulator-control unit  
U0155 Lost communication with the gauge control module  

DTC (Parking and Back-Up Sensor Control Unit)

  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  
    U0065-00 CAN Gateway F-CAN ch D Bus Off  
    U3000-49 CAN Gateway Internal Failure  

    Is DTC U0029-00, U0047-00, U0056-00, U0065-00, and/or U3000-49 indicated?

    YES 

    Go to the troubleshooting for CAN gateway system DTC (s) .

    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 Unit Check.

    F-CAN Bus Connected Unit Check

    Does the parking and back-up sensor control unit detect the CAN gateway Bus channel B?

    Bus B is Not Available

    Go to step 3.

    Bus B is Available

    Go to step 4.

  3. Open wire check (F-CAN B lines)

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

    -2. Disconnect the following connectors.

    CAN gateway 16P connector
    Parking and back-up sensor control unit 24P connector

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

    Test condition Vehicle OFF (LOCK) mode
    CAN gateway 16P connector: disconnected
    Parking and back-up sensor control unit 24P connector: disconnected
    Test point 1 CAN gateway 16P connector (female terminals) No. 6:
    Test point 2 Parking and back-up sensor control unit 24P connector No. 22
    Test point 1 CAN gateway 16P connector (female terminals) No. 14:
    Test point 2 Parking and back-up sensor control unit 24P connector No. 10
    GHH397524Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    The F-CAN B_H and F-CAN B_L wires are OK. Check for poor connections or loose terminals at the CAN gateway and the parking and back-up sensor control unit. If they are OK, replace the parking and back-up sensor control unit .

    NO 

    Repair an open in F-CAN B_H or F-CAN B_L wire between the CAN gateway and the parking and back-up sensor control unit.

  4. F-CAN circuit communication check (Transmitting control unit)

    -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

    According to the detected DTC on the following table, make sure that the transmitting control unit detects the CAN gateway Bus channel (s) normally.

    DTC Transmitting control unit Detected CAN gateway Bus channel (s) at normal
    U0101 *1 TCM A, D
    U0101 *2 TCM A
    U0122 VSA modulator-control unit A, B
    U0155 Gauge control module C

    *1: A/T

    *2: CVT

    Is it detected normally?

    Detected normal

    Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the transmitting control unit and the CAN gateway.

    Any of control units are Not Available for Bus A

    Go to step 5.

    Any of control units are Not Available for Bus B

    Go to step 6.

    Any of control units are Not Available for Bus C

    Go to step 7.

    Any of control units are Not Available for Bus D

    Go to step 8.

  5. Open wire check (F-CAN A lines)

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

    -2. According to the detected DTC on the following table, disconnect the transmitting control unit connector (s).

    DTC Connector
    - CAN gateway 16P connector
    U0101 *1 TCM connector A (23P)
    U0101 *2 TCM 50P connector
    U0122 VSA modulator-control unit 46P connector

    *1: A/T

    *2: CVT

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

    Test condition Vehicle OFF (LOCK) mode
    CAN gateway 16P connector: disconnected
    Transmitting control unit connector (s) for indicated DTCs: disconnected
    DTC Circuit name Test point 1 (Receiving control unit) Test point 2 (Transmitting control unit)
    Connector Terminal Connector Terminal
    U0101 *1 F-CAN A_H CAN gateway 16P connector (female terminals): No. 3 TCM connector A (23P) No. 19
    F-CAN A_L No. 11 No. 18
    U0101 *2 F-CAN A_H CAN gateway 16P connector (female terminals): No. 3 TCM 50P connector No. 3
    F-CAN A_L No. 11 No. 11
    U0122 F-CAN A_H CAN gateway 16P connector (female terminals): No. 3 VSA modulator-control unit 46P connector No. 20
    F-CAN A_L No. 11 No. 21

    *1: A/T

    *2: CVT

    GHH397528Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    The F-CAN A_H wire and the F-CAN A_L wire are OK.

    According to the detected DTC on the following table, substitute or replace the control unit based on the instructions (see table).

    DTC Operation for transmitting control unit
    U0101 Substitute a known-good TCM (A/T , CVT ), then recheck. If DTC U0101 goes away after substitution, replace the original TCM (A/T , CVT ).
    DTC Operation for transmitting control unit
    U0122 Replace the VSA modulator-control unit .

    NO 

    Repair an open in F-CAN A_H or F-CAN A_L wire between the CAN gateway and the transmitting control unit.

  6. Open wire check (F-CAN B lines)

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

    -2. According to the detected DTC on the following table, disconnect the transmitting control unit connector (s).

    DTC Connector
    - CAN gateway 16P connector
    U0122 VSA modulator-control unit 46P connector

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

    Test condition Vehicle OFF (LOCK) mode
    CAN gateway 16P connector: disconnected
    Transmitting control unit connector (s) for indicated DTCs: disconnected
    DTC Circuit name Test point 1 (Receiving control unit) Test point 2 (Transmitting control unit)
    Connector Terminal Connector Terminal
    U0122 F-CAN B_H CAN gateway 16P connector (female terminals): No. 3 VSA modulator-control unit 46P connector No. 24
    F-CAN B_L No. 11 No. 25
    GHH397530Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    The F-CAN B_H wire and the F-CAN B_L wire are OK.

    According to the detected DTC on the following table, substitute or replace the control unit based on the instructions (see table).

    DTC Operation for transmitting control unit
    U0122 Replace the VSA modulator-control unit .

    NO 

    Repair an open in F-CAN B_H or F-CAN B_L wire between the CAN gateway and the transmitting control unit.

  7. Open wire check (F-CAN C lines)

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

    -2. According to the detected DTC on the following table, disconnect the transmitting control unit connector (s).

    DTC Connector
    - CAN gateway 16P connector
    U0155 Gauge control module connector A (32P)

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

    Test condition Vehicle OFF (LOCK) mode
    CAN gateway 16P connector: disconnected
    Transmitting control unit connector (s) for indicated DTCs: disconnected
    DTC Circuit name Test point 1 (Receiving control unit) Test point 2 (Transmitting control unit)
    Connector Terminal Connector Terminal
    U0155 F-CAN C_H CAN gateway 16P connector (female terminals): No. 5 Gauge control module connector A (32P) No. 20
    F-CAN C_L No. 13 No. 21
    GHH397532Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    The F-CAN C_H wire and the F-CAN C_L wire are OK.

    According to the detected DTC on the following table, substitute or replace the control unit based on the instructions (see table).

    DTC Operation for transmitting control unit
    U0155 Substitute a known-good gauge control module , then recheck. If DTC U0155 goes away after substitution, replace the original gauge control module .

    NO 

    Repair an open in F-CAN C_H or F-CAN C_L wire between the CAN gateway and the transmitting control unit.

  8. Open wire check (F-CAN D lines)

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

    -2. According to the detected DTC on the following table, disconnect the transmitting control unit connectors.

    DTC Connector
    - CAN gateway 16P connector
    U0101 TCM connector A (23P)

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

    Test condition Vehicle OFF (LOCK) mode
    CAN gateway 16P connector: disconnected
    Transmitting control unit connector (s) for indicated DTCs: disconnected
    DTC Circuit name Test point 1 (Receiving control unit) Test point 2 (Transmitting control unit)
    Connector Terminal Connector Terminal
    U0101 F-CAN D_H CAN gateway 16P connector (female terminals): No. 7 TCM connector A (23P) No. 13
    F-CAN D_L No. 15 No. 12
    GHH397534Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    The F-CAN D_H wire and the F-CAN D_L wire are OK.

    According to the detected DTC on the following table, substitute or replace the control unit based on the instructions (see table).

    DTC Operation for transmitting control unit
    U0101 Substitute a known-good TCM , then recheck. If DTC U0101 goes away after substitution, replace the original TCM .

    NO 

    Repair an open in F-CAN D_H or F-CAN D_L wire between the CAN gateway and the transmitting control unit.