DTC U1280 (MICU) (2016 2017 2018)

DTC U1280  : B-CAN communication bus line error (BUS-OFF)

DTCs

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

1. Problem verification

   -1. Clear the DTCs with the HDS.

   -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 B-CAN 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	32P connector
   Climate control unit	Connector A (32P)
   Front seat heater control unit	14P connector
   Keyless access control unit (With keyless access system)	Connector C (20P)
   Immobilizer-keyless control unit (Without keyless access system)	7P connector
   Automatic lighting control unit-sensor	7P connector
   Audio unit with display audio type	Connector B (20P)
   Audio unit with color audio type	Connector C (24P)
   Audio-navigation unit	Connector B (20P)

   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

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

   -2. Disconnect the following connectors.

   Under-dash fuse/relay box connector D (24P) Under-dash fuse/relay box connector H (20P)

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

   Test condition	Vehicle OFF (LOCK) mode Under-dash fuse/relay box connector D (24P): disconnected Under-dash fuse/relay box connector H (20P): disconnected
   Test point 1	Under-dash fuse/relay box connector D (24P) No. 2
   Test point 2	Body ground

   Test point 1	Under-dash fuse/relay box connector D (24P) No. 1
   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 lines) 2

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

   Test condition	Vehicle OFF (LOCK) mode Under-dash fuse/relay box connector D (24P): disconnected Under-dash fuse/relay box connector H (20P): disconnected
   Test point 1	Under-dash fuse/relay box connector H (20P) No. 11
   Test point 2	Body ground

   Test point 1	Under-dash fuse/relay box connector H (20P) No. 12
   Test point 2	Body ground

   Is there continuity?

   YES 

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

   NO 

   Go to step 5.

5. Shorted wire check (B-CAN_L to B-CAN_H line) 1

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

   Test condition	Vehicle OFF (LOCK) mode Under-dash fuse/relay box connector D (24P): disconnected Under-dash fuse/relay box connector H (20P): disconnected
   Test point 1	Under-dash fuse/relay box connector D (24P) No. 2
   Test point 2	Under-dash fuse/relay box connector D (24P) No. 1

   Is there continuity?

   YES 

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

   NO 

   Go to step 6.

6. Shorted wire check (B-CAN_L to B-CAN_H line) 2

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

   Test condition	Vehicle OFF (LOCK) mode Under-dash fuse/relay box connector D (24P): disconnected Under-dash fuse/relay box connector H (20P): disconnected
   Test point 1	Under-dash fuse/relay box connector H (20P) No. 11
   Test point 2	Under-dash fuse/relay box connector H (20P) No. 12

   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 .