DTC Troubleshooting: U1280
DTC U1280:
 Communication Bus Line Error (BUS-OFF)
  1. Clear the DTCs with the HDS.
  1. Turn the ignition switch to LOCK (0) and then back to ON (II).
  1. Wait for 6 seconds or more.
  1. Check for DTCs with the HDS.
Is DTC U1280 indicated?
YES -
Go to Step 5 .
NO -
Intermittent failure, the system is OK at this time. Check for loose or poor connections, or worn/shorted wires. If the connections are good, check the battery condition and the charging system.■
  1. Turn the ignition switch to LOCK (0).
  1. 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
    Passenger's MICU
    Passenger's under-dash fuse/relay box connector A (38P)
    Door multiplex control unit
    37P connector
    Gauge control module
    32P connector
    Immobilizer-keyless control unit
    7P connector
    Audio unit
    Connector B (20P)
    Heater control unit/Climate control unit
    Connector B (12P)
    Hands Free Telephone control unit *1
    28P connector
    Headlight leveling control unit *2
    16P connector
    Automatic lighting/rain sensor *3
    6P connector
    Power seat control unit *4
    40P connector
    Parking and back-up sensor control unit *5
    16P connector

    *1:
    With Hands Free Telephone system
    *2:
    With headlight leveling system
    *3:
    With automatic wiper
    *4:
    With DPMS
    *5:
    With parking and back-up sensor system

Is DTC U1280 indicated with each individual unit disconnected?
YES -
Go to Step 7 .
NO -
Go to the input test for the control unit that was disconnected when DTC U1280 did not reset and perform all power and ground input tests. If the tests prove OK, replace that unit.■
  1. Turn the ignition switch to LOCK (0).
  1. Disconnect each control unit connector in the table.
    Control Unit
    Connector
    Passenger's MICU
    Passenger's under-dash fuse/relay box connector A (38P)
    Door multiplex control unit
    37P connector
    Gauge control module
    32P connector
    Immobilizer-keyless control unit
    7P connector
    Audio unit
    Connector B (20P)
    Heater control unit/Climate control unit
    Connector B (12P)
    Hands Free Telephone control unit *1
    28P connector
    Headlight leveling control unit *2
    16P connector
    Automatic lighting/rain sensor *3
    6P connector
    Power seat control unit *4
    40P connector
    Parking and back-up sensor control unit *5
    16P connector

    *1:
    With Hands Free Telephone system
    *2:
    With headlight leveling system
    *3:
    With automatic wiper
    *4:
    With DPMS
    *5:
    With parking and back-up sensor system

  1. Disconnect driver's under-dash fuse/relay box connector P (20P).
  1. Check for continuity between driver's under-dash fuse/relay box connector P (20P) No. 5 and No. 6 terminals.
Is there continuity?
YES -
A short between the B-CAN wires.■
NO -
Go to Step 11 .
  1. Check for continuity between body ground and driver's under-dash fuse/relay box connector P (20P) No. 5 and No. 6 terminals individually.
Is there continuity?
YES -
A short to ground in the wire.■
NO -
Go to Step 12 .
  1. Turn the ignition switch to ON (II).
  1. Measure the voltage between body ground and driver's under-dash fuse/relay box connector P (20P) No. 5 and No. 6 terminals individually.
Is there voltage?
YES -
A short to power in the wire.■
NO -
Faulty driver's MICU, replace the driver's under-dash fuse/relay box.■