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DTC : U1281, U128D

DTC U1281  : Auto leveling control unit lost communication with MICU DTC U128D  : Auto leveling control unit lost communication with Gauge control unit

NOTE: 

DTC Description DTC
U1281 Auto leveling control unit lost communication with MICU  
U128D Auto leveling control unit lost communication with Gauge control unit  

DTC (Headlight Leveling Control Unit)

NOTE:  If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A - Refer to:

Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks .

  1. Problem verification

    -1. Clear the DTCs with the HDS.

    Clear DTCs

    - 2. Turn the vehicle to the OFF (LOCK) mode and then the ON mode.

    - 3. Wait for at least 6 seconds.

    - 4. Check for DTCs with the HDS.

    DTC Description DTC
    U1281 Auto leveling control unit lost communication with MICU  
    U128D Auto light control unit lost communication with gauge control module  

    Are DTC U1281 or U128D indicated?

    YES 

    Go to step 2.

    NO 

    Intermittent failure, the system is OK at this time. Check for loose or poor connections.

  2. Open wire check (B-CAN_H, B-CAN_L line)

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

    - 2. Disconnect the receiving control unit connector.

    Headlight leveling control unit 12P connector

    - 3. Disconnect the transmitting control unit connectors.

    Gauge control module 32P connector
    Under-dash fuse/relay box connector M (12P)

    - 4. Check for continuity between the receiving control unit and the transmitting control unit on the B-CAN_H circuit and the B-CAN_L circuit as specified in the table while in the vehicle OFF (LOCK) mode.

    DTC CIRCUIT NAME RECEIVING CONTROL UNIT TRANSMITTING CONTROL UNIT
    U1281 Auto leveling control unit lost communication with MICU B-CAN_H Headlight Leveling Control Unit 12P Connector No. 7 Under-Dash Fuse/Relay Box Connector M (12P) No. 7
    B-CAN_L Headlight Leveling Control Unit 12P Connector No. 8 Under-Dash Fuse/Relay Box Connector M (12P) No. 1
    U128D Auto light control unit lost communication with gauge control module B-CAN_H Headlight Leveling Control Unit 12P Connector No. 7 Gauge control module 32P connector No. 26 - Refer to:
    Gauge Control Module Connector for Inputs and Outputs (2016 2017 20180 or
    Gauge Control Module Connector for Inputs and Outputs (2019) or
    Gauge Control Module Connector for Inputs and Outputs (2020 2021) .
    B-CAN_L Headlight Leveling Control Unit 12P Connector No. 8 Gauge control module 32P connector No. 27 - Refer to:
    Gauge Control Module Connector for Inputs and Outputs (2016 2017 20180 or
    Gauge Control Module Connector for Inputs and Outputs (2019) or
    Gauge Control Module Connector for Inputs and Outputs (2020 2021) .

    Is there continuity?

    YES 

    The B-CAN_L to B-CAN_H wire is OK. Go to step 3.

    NO 

    Repair an open or high resistance in the B-CAN_H and/or B-CAN_L wire (S) between the receiving control unit and the transmitting control unit.

  3. Determine possible failure area (the receiving control unit or the transmitting control unit)

    -1. Reconnect all connectors.

    - 2. Turn the vehicle to the ON mode.

    - 3. Clear the DTCs with the HDS.

    Clear DTCs

    - 4. Check for DTCs with the HDS.

    DTC Description DTC
    U1281 Auto leveling control unit lost communication with MICU  
    U128D Auto leveling control unit lost communication with Gauge control unit  

    Are DTC U1281 and U128D indicated?

    YES 

    Check for loose terminals and poor connections in the headlight leveling control unit connector. Check is OK, replace the Headlight Leveling Control Unit - Removal and Installation .

    NO 

    The headlight leveling control unit is OK at this time. Update or replace the transmitting control unit. (Refer to the DTC code shown on the display, and then update or replace the control unit based on the instructions in the table below.)

    DTC TRANSMITTING CONTROL UNIT
    U1281 Auto leveling control unit lost communication with MICU Update or replace the MICU
    U128D Auto light control unit lost communication with gauge control module Replace the gauge control module