Honda HR-V: DTC U1280 (MICU) B-CAN Communication Bus Line Error (BUS-OFF)

DTC (MICU)

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.

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.

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.

Clear DTCs

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.

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.

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.

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.

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.

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