DTC Troubleshooting: U1280
DTC U1280: Communication Bus Line Error (BUS-OFF)
DTC Description
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.

1.
Problem verification:

Problem verification
?1.
Turn the vehicle to the ON mode.

?2.
Clear the DTCs with the HDS.


?3.
Turn the vehicle to the OFF (LOCK) mode and then the ON mode.

?4.
Wait for at least 6 seconds.

?5.
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:

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. Turn the vehicle to the ON mode, clear the DTC, then recheck for DTCs after each unit is disconnected.
Control Unit
Connector
Gauge control module
32P connector
Climate control unit
32P connector
Automatic lighting control unit-sensor
(USA and Canada models)
5P connector
Automatic lighting control unit-sensor
(Mexico models)
7P connector
Keyless access control unit
(with keyless access system)
Connector C (20P)
Immobilizer-keyless control unit
(without keyless access system)
7P connector
Audio-navigation unit (with navigation)
Connector A (24P)
Audio unit (without navigation)
Connector A (24P)
Multipurpose camera unit
20P connector

DTC Description
DTC
U1280 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):

Shorted wire check (B-CAN lines)
?1.
Disconnect the following connector.
Under-dash fuse/relay box connector G (10P)

?2.
Check for continuity between test points 1 and 2 individually.
Test condition
Vehicle OFF (LOCK) mode
Under-dash fuse/relay box connector G (10P): disconnected
Test point 1
Under-dash fuse/relay box connector G (10P) No. 2
Test point 2
Body ground

Test point 1
Under-dash fuse/relay box connector G (10P) No. 3
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):

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 G (10P): disconnected
Test point 1
Under-dash fuse/relay box connector G (10P) No. 2
Test point 2
Under-dash fuse/relay box connector G (10P) No. 3

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.?