DTC U1280: Communication Bus Line Error (BUS-OFF)
| DTC Description | DTC |
|---|---|
| U1280 B-CAN 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 ChecksBody Electrical Troubleshooting - B-CAN System Diagnosis Test Mode 1 and Test Mode 2 (without the HDS)Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode B - Control Unit Not CommunicatingBody Electrical Troubleshooting - B-CAN System Diagnosis Test Mode C - No DTCs and Output Won't Shut OFFBody Electrical Troubleshooting - B-CAN System Diagnosis Test Mode D - No DTCs and Output Won't Turn ON .
NOTE: Refer to the Electrical Wiring Diagrams for the location of the under-dash fuse/relay box connectors.
- 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 Connector A (32P) Climate control unit 32P connector Power window master switch 37P connector Power seat control unit Connector B (40P) Power tailgate control unit Connector A (14P) Automatic lighting/rain sensor 5P connector Automatic lighting control unit/sensor 7P connector Audio unit without display audio Connector B (20P) Audio unit with display audio Connector C (20P) Audio-navigation unit Connector C (20P) Keyless access control unit Connector B (28P) Immobilizer-keyless control unit 7P connector Multi-information display unit Connector A (32P) Clear DTCs
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 K (12P) Under-dash fuse/relay box connector Q (16P)
3. Check for continuity between test points 1 and 2 individually.
Test condition Vehicle OFF (LOCK) mode Under-dash fuse/relay box connector K (12P): disconnected
Under-dash fuse/relay box connector Q (16P): disconnected
Test point 1 Under-dash fuse/relay box connector K (12P) No. 1 Test point 2 Body ground Test point 1 Under-dash fuse/relay box connector K (12P) No. 2 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 individually.
Test condition IG LOCK (0) or OFF mode Under-dash fuse/relay box connector K (12P): disconnected
Under-dash fuse/relay box connector Q (16P): disconnected
Test point 1 Under-dash fuse/relay box connector Q (16P) No. 5 Test point 2 Body ground Test point 1 Under-dash fuse/relay box connector Q (16P) No. 6 Test point 2 Body ground Is there continuity?
YES
Repair a short to ground in the B-CAN wires.
NO
The B-CAN wires are not shorted to ground. 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 K (12P): disconnected
Under-dash fuse/relay box connector Q (16P): disconnected
Test point 1 Under-dash fuse/relay box connector K (12P) No. 1 Test point 2 Under-dash fuse/relay box connector K (12P) No. 2 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 K (12P): disconnected
Test point 1 Under-dash fuse/relay box connector Q (16P) No. 5 Test point 2 Under-dash fuse/relay box connector Q (16P) No. 6 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 .