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Home >> Honda >> 2021 >> Pilot Special Edition, AWD >> Repair and Diagnosis >> Accessories & Equipment >> Exterior Lights >> Automatic Lighting System - Diagnostics >> DTC Troubleshooting >> DTC : U1281, U128D (Automatic Lighting/Rain Sensor) (2016 2017 2018)

DTC : U1281, U128D (Automatic Lighting/Rain Sensor) (2016 2017 2018)

DTC U1281  : Rain light sensor lost communication with MICU DTC U128D  : Rain Light Sensor Unit lost communication with gauge control module

NOTE: 

DTC Description DTC
U1281 Rain light sensor lost communication with MICU  
U128D Rain Light Sensor Unit lost communication with gauge control module  

DTC (Automatic Lighting/Rain Sensor)

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 Rain light sensor lost communication with MICU  
    U128D Rain Light Sensor 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.

    Automatic lighting/rain sensor 5P 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 Rain light sensor lost communication with MICU B-CAN_H Automatic lighting/rain sensor 5P connector No. 4 - Refer to:
    Automatic Lighting/Rain Sensor Connector for Inputs and Outputs (2016 2017 2018)
    Under-Dash Fuse/Relay Box Connector M (12P) No. 7
    B-CAN_L Automatic lighting/rain sensor 5P connector No. 3 - Refer to:
    Automatic Lighting/Rain Sensor Connector for Inputs and Outputs (2016 2017 2018)
    Under-Dash Fuse/Relay Box Connector M (12P) No. 1
    U128D Rain Light Sensor Unit lost communication with gauge control module B-CAN_H Automatic lighting/rain sensor 5P connector No. 4 - Refer to:
    Automatic Lighting/Rain Sensor Connector for Inputs and Outputs (2016 2017 2018)
    Gauge control module 32P connector No. 26 -
    Refer to:
    Gauge Control Module Connector for Inputs and Outputs (2016 2017 2018)
    B-CAN_L Automatic lighting/rain sensor 5P connector No. 3 - Refer to:
    Automatic Lighting/Rain Sensor Connector for Inputs and Outputs (2016 2017 2018)
    Gauge control module 32P connector No. 27 -
    Refer to:
    Gauge Control Module Connector for Inputs and Outputs (2016 2017 2018)

    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 Rain Light Sensor Unit lost communication with MICU  
    U128D Rain Light Sensor Unit lost communication with gauge control module  

    Are DTC U1281 and U128D indicated?

    YES 

    Check for loose terminals and poor connections in the automatic lighting/rain sensor connector. Check is OK, replace the Automatic Lighting/Rain Sensor - Removal and Installation .

    NO 

    The automatic lighting/rain sensor 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 Rain Light Sensor Unit lost communication with MICU Update or replace the MICU
    U128D Rain Light Sensor Unit lost communication with gauge control module Replace the gauge control module