DTC : U1281, U128D (Keyless Access Control Unit) (2019 2020 2021)

DTC U1281  : Keyless Access Control Unit lost communication with MICU

DTC U128D  : Keyless Access Control Unit lost communication with Gauge Control Module

NOTE: 

• If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A - Go to: Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks .
• Refer to the DTC code shown on the display, and then inspect the connectors and terminals based on the instructions in the table below.
• The DTC may be stored due to the grounding failure or the power source failure at the transmitting control unit (the grounding inspection and the power source inspection on each control unit are required prior to this checking process).

DTC (Keyless Access Control Unit)

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 Keyless Access Control Unit lost communication with MICU
   U128D Keyless Access 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.

   Keyless access/TPMS control unit connector C (20P)

   - 3. Disconnect the transmitting control unit connectors.

   Gauge control module connector A (32P)

   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	B-CAN_H	Keyless access/TPMS control unit connector C (20P) No. 1 - Refer to: Keyless Access/TPMS Control Unit Connector for Inputs and Outputs (2019 2020 2021) .	Under-Dash Fuse/Relay Box Connector M (12P) No. 7
   	B-CAN_L	Keyless access/TPMS control unit connector C (20P) No. 11 - Refer to: Keyless Access/TPMS Control Unit Connector for Inputs and Outputs (2019 2020 2021) .	Under-Dash Fuse/Relay Box Connector M (12P) No. 1
   U128D	B-CAN_H	Keyless access/TPMS control unit connector C (20P) No. 1 - Refer to: Keyless Access/TPMS Control Unit Connector for Inputs and Outputs (2019 2020 2021) .	Gauge control module connector A (32P) No. 30 - Refer to: Gauge Control Module Connector for Inputs and Outputs (2019) or Gauge Control Module Connector for Inputs and Outputs (2020 2021) .
   	B-CAN_L	Keyless access/TPMS control unit connector C (20P) No. 11 - Refer to: Keyless Access/TPMS Control Unit Connector for Inputs and Outputs (2019 2020 2021) .	Gauge control module connector A (32P) No. 31 - Refer to: 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_H wire and the B-CAN_L wire are OK, Refer to the DTC shown on the display, then replace the control unit based on the instructions (see table).

   DTC	Operation for transmitting control unit
   U1281	Under-dash fuse relay box
   U128D	Gauge control module

   NO 

   Repair an open or high resistance in the B-CAN_H and/or B-CAN_L wire.