Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC U1280: Communication Bus Line Error (a bus OFF state is detected by Telematics-ECU) (2016-18)
| DTC Description | DTC |
|---|---|
| U1280 Communication Bus Line Error (a bus OFF state is detected by Telematics-ECU) |
DTC (Telematics System)
- 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 D - No DTCs and Output Wont Turn ON (2013-18), or Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode C - No DTCs and Output Wont Shut OFF (2013-18), or Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode 1 and Test Mode 2 (without the HDS) (2016-18), or Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks (2016-18), or Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode B - Control Unit Not Communicating (2016-18) .
- Check the connectors for poor connections or loose terminals.
- MICU DTC check:
Check for MICU DTCs with the HDS.
DTC Description DTC U1280 Communication bus line error (BUS-OFF) Is DTC U1280 indicated?
YES
Go to MICU DTC U1280 troubleshooting .
NO
Go to step 2.
- Problem verification:
Check for DTCs without the HDS .
Is DTC U1280 indicated?
YES
The failure is duplicated, go to step 3.
NO
Intermittent failure, the system is OK at this time.
- Open wire check (B-CAN_H line, B-CAN_L line):
Press the engine start/stop button to select the OFF mode.
- 2. Disconnect the following connectors.
Telematics control unit connector A (36P) Under-dash fuse/relay box connector M (7P) - 3. Check for continuity between test points 1 and 2.
Test condition OFF mode Telematics control unit connector A (36P): disconnected Under-dash fuse/relay box connector M (7P): disconnected Test circuit B-CAN_H Test point 1 Telematics control unit connector A (36P) No. 33 (PNK) Test point 2 Under-dash fuse/relay box connector M (7P) No. 2 (PNK) Test circuit B-CAN_L Test point 1 Telematics control unit connector A (36P) No. 34 (BLU) Test point 2 Under-dash fuse/relay box connector M (7P) No. 1 (BLU) Is there continuity?
YES
Replace the telematics control unit .
NO
Repair an open in the wire(s) between the telematics control unit and the under-dash fuse/relay box.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.