Vehicle system

Module Communication Network Codes

U codes for lost communication between modules on the CAN or LIN network. When one module stops responding, the others report it, which is why it is normal to see several U codes at once.

The cause is usually power, ground or network wiring rather than the module itself. A weak battery or a voltage drop while cranking can leave U codes in almost every module in the vehicle.

Most searched codes in this system

  • U0100: lost communication with the engine computer.
  • U0101: lost communication with the transmission module.
  • U0121: lost communication with the ABS module.
  • U0140: lost communication with the body control module.
  • U0001 and U0073: high-speed CAN bus.

What to check first

  1. Charge and test the battery. Clear the codes and see which ones come back.
  2. Identify the module that is not responding: all the others point to it.
  3. Check that module's fuses, ground and connector.
  4. With the ignition off, the resistance between pins 6 and 14 of the OBD2 connector should be about 60 ohms.

All codes in this system

149 codes, page 1 of 2

CodeMeaningSeverity
U0001 High Speed CAN Communication Bus High
U0002 High Speed CAN Communication Bus Performance High
U0003 High Speed CAN Communication Bus (+) Open High
U0004 High Speed CAN Communication Bus (+) Low High
U0005 High Speed CAN Communication Bus (+) High High
U0006 High Speed CAN Communication Bus (-) Open High
U0007 High Speed CAN Communication Bus (-) Low High
U0008 High Speed CAN Communication Bus (-) High High
U0009 High Speed CAN Communication Bus (-) Shorted to Bus (+) High
U0010 Medium Speed CAN Communication Bus High
U0011 Medium Speed CAN Communication Bus Performance High
U0012 Medium Speed CAN Communication Bus (+) Open High
U0013 Medium Speed CAN Communication Bus (+) Low High
U0014 Medium Speed CAN Communication Bus (+) High High
U0015 Medium Speed CAN Communication Bus (-) Open High
U0016 Medium Speed CAN Communication Bus (-) Low High
U0017 Medium Speed CAN Communication Bus (-) High High
U0018 Medium Speed CAN Communication Bus (+) Shorted to Bus (-) High
U0019 Low Speed CAN Communication Bus High
U0020 Low Speed CAN Communication Bus Performance High
U0021 Low Speed CAN Communication Bus (+) Open High
U0022 Low Speed CAN Communication Bus (+) Low High
U0023 Low Speed CAN Communication Bus (+) High High
U0024 Low Speed CAN Communication Bus (-) Open High
U0025 Low Speed CAN Communication Bus (-) Low High
U0026 Low Speed CAN Communication Bus (-) High High
U0027 Low Speed CAN Communication Bus (+) Shorted to Bus (-) High
U0028 Vehicle Communication Bus A High
U0029 Vehicle Communication Bus A Performance High
U0073 Control Module Communication Bus A Off High
U0074 Control Module Communication Bus B Off High
U0075 Control Module Communication Bus C Off High
U0076 Control Module Communication Bus D Off High
U0077 Control Module Communication Bus E Off High
U0100 Lost Communication With ECM/PCM A Critical
U0101 Lost Communication with TCM High
U0102 Lost Communication with Transfer Case Control Module Medium
U0103 Lost Communication with Gear Shift Module High
U0104 Lost Communication with Cruise Control Module Low
U0105 Lost Communication with Fuel Injector Control Module High
U0106 Lost Communication with Glow Plug Control Module Low
U0107 Lost Communication with Throttle Actuator Control Module High
U0108 Lost Communication with Alternative Fuel Control Module Medium
U0109 Lost Communication with Fuel Pump Control Module High
U0110 Lost Communication with Drive Motor Control Module A Critical
U0111 Lost Communication with Battery Energy Control Module A Critical
U0112 Lost Communication with Battery Energy Control Module B Critical
U0114 Lost Communication with Four-Wheel Drive Clutch Control Module Medium
U0115 Lost Communication with ECM/PCM B High
U0117 Lost Communication with Power Take-Off (PTO) Control Module Low
U0121 Lost Communication with Anti-Lock Brake System (ABS) Control Module High
U0122 Lost Communication with Vehicle Dynamics Control Module High
U0123 Lost Communication with Yaw Rate Sensor Module Medium
U0124 Lost Communication with Lateral Acceleration Sensor Module Medium
U0125 Lost Communication with Multi-axis Acceleration Sensor Module Medium
U0126 Lost Communication with Steering Angle Sensor Module Medium
U0127 Lost Communication with Tire Pressure Monitor Module Low
U0128 Lost Communication with Park Brake Control Module High
U0129 Lost Communication With Brake System Control Module High
U0130 Lost Communication With Steering Effort Control Module Medium
U0131 Lost Communication With Power Steering Control Module High
U0132 Lost Communication With Ride Level Control Module Medium
U0136 Lost Communication With Differential Control Module Low
U0137 Lost Communication With Trailer Brake Control Module High
U0138 Lost Communication With All Terrain Control Module Low
U0140 Lost Communication With Body Control Module Medium
U0141 Lost Communication With Body Control Module A Medium
U0142 Lost Communication With Body Control Module B Low
U0143 Lost Communication With Body Control Module C Medium
U0144 Lost Communication With Body Control Module D Medium
U0145 Lost Communication With Body Control Module E Medium
U0146 Lost Communication With Gateway A High
U0151 Lost Communication With Restraints Control Module High
U0152 Lost Communication With Side Restraints Control Module Left High
U0153 Lost Communication With Side Restraints Control Module Right High
U0154 Lost Communication With Restraints Occupant Classification System Module High
U0155 Lost Communication With Instrument Panel Cluster (IPC) Control Module Medium
U0156 Lost Communication With Information Center A Low
U0158 Lost Communication With Head Up Display Low
U0159 Lost Communication With Parking Assist Control Module Low
U0160 Lost Communication With Audible Alert Control Module Low
U0161 Lost Communication With Compass Module Low
U0162 Lost Communication With Navigation Display Module Low
U0163 Lost Communication With Navigation Control Module Low
U0164 Lost Communication With HVAC Control Module Low
U0165 Lost Communication With HVAC Control Module Rear Low
U0166 Lost Communication With Auxiliary Heater Control Module Low
U0167 Lost Communication With Vehicle Immobilizer Control Module High
U0168 Lost Communication With Vehicle Security Control Module Medium
U0169 Lost Communication With Sunroof Control Module Low
U0170 Lost Communication With Restraint System Sensor A High
U0171 Lost Communication With Restraint System Sensor B High
U0172 Lost Communication With Restraint System Sensor C High
U0173 Lost Communication With Restraint System Sensor D High
U0180 Lost Communication With Automatic Lighting Control Module Low
U0181 Lost Communication With Headlamp Leveling Control Module Low
U0182 Lost Communication With Lighting Control Module Front Medium
U0183 Lost Communication With Lighting Control Module Rear Medium
U0184 Lost Communication With Radio Low
U0185 Lost Communication With Antenna Control Module Low

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