DTC : U1280 (MICU) (2019 2020 2021)

DTC U1280  : Communication bus line error (BUS-OFF)

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 .

DTC (MICU)

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
   U1280 Communication bus line error (BUS-OFF)

   Is DTC U1280 indicated?

   YES 

   Go to step 2.

   NO 

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

2. B-CAN related units check

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

   - 2. Disconnect the appropriate connector at each control unit in the table one at a time. Clear the DTC, then recheck for DTCs after each unit is disconnected.

   Control Unit	Connector
   Gauge Control Module	Connector A (32P)
   Climate Control Unit	Connector A (32P)
   HVAC Control Unit	Connector A (32P)
   Power Window Master Switch	37P connector
   Headlight Leveling Control Unit	12P connector
   Automatic Lighting Control Unit-Sensor	5P connector
   Automatic Lighting/Rain Sensor	5P connector
   Front Seat Heater Control Unit	14P connector
   Keyless Access/TPMS Control Unit	Connector C (20P)
   Power Tailgate Control Unit	Connector A (24P)
   Parking And Back-Up Sensor Control Unit	16P connector
   Power Seat Control Unit	Connector A (20P)
   Multipurpose Camera Unit Connector for Inputs and Outputs	20P Connector
   Audio Unit Removal and Installation [Color Audio Type (5-inch Screen)]	Connector C (28P)
   Ventilated Seat Control Unit	14P connector
   Second Row Seat Heater Control Unit	14P connector
   Telematics Control Unit	32P connector
   Wireless Charger	7P connector
   Left Side BSI Radar Unit	6P connector
   Right Side BSI Radar Unit	6P connector

   DTC Description	DTC
   U1280 B-CAN Communication Bus Line Error (BUS-OFF)

   Is DTC U1280 indicated with each individual unit disconnected?

   YES 

   Leave the connectors disconnected, and go to step 3.

   NO 

   Replace the control unit that was disconnected when DTC U1280 did not reset.

3. Shorted wire check (B-CAN lines)

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

   - 2. Disconnect the following connector.

   Under-dash fuse/relay box connector M (12P)

   Under-dash fuse/relay box connector R (16P)

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

   Test condition	Vehicle OFF (LOCK) mode Under-dash fuse/relay box connector M (12P): disconnected Under-dash fuse/relay box connector R (16P): disconnected
   Test point 1	Under-Dash Fuse/Relay Box Connector M (12P) No. 1
   Test point 2	Body ground

   Test point 1	Under-Dash Fuse/Relay Box Connector M (12P) No. 7
   Test point 2	Body ground

   Test point 1	Under-Dash Fuse/Relay Box Connector R (16P) No. 10
   Test point 2	Body ground

   Test point 1	Under-Dash Fuse/Relay Box Connector R (16P) No. 11
   Test point 2	Body ground

   Is there continuity?

   YES 

   Repair a short to ground in the B-CAN wires.

   NO 

   Go to step 4.

4. Shorted wire check (B-CAN_L to B-CAN_H line)

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

   Test condition	Vehicle OFF (LOCK) mode Under-dash fuse/relay box connector M (12P): disconnected Under-dash fuse/relay box connector R (16P): disconnected
   Test point 1	Under-Dash Fuse/Relay Box Connector M (12P) No. 1
   Test point 2	Under-Dash Fuse/Relay Box Connector M (12P) No. 7

   Test point 1	Under-Dash Fuse/Relay Box Connector R (16P) No. 10
   Test point 2	Under-Dash Fuse/Relay Box Connector R (16P) No. 11

   Is there continuity?

   YES 

   Repair a short in the B-CAN_L to B-CAN_H wire.

   NO 

   The B-CAN_L to B-CAN_H wire is OK. Faulty MICU; replace the Under-Dash Fuse/Relay Box - Removal and Installation .