Network Codes
1,532 OBD-II diagnostic trouble codes in this category.
Showing page 11 of 16 (1,532 codes total)
| Code | Description | Subsystem | Severity |
|---|---|---|---|
| U066B | Lost Communication With Turbocharger/Supercharger Bypass Valve B Position Sensor | Module Communication | High |
| U066C | Lost Communication With Exhaust Heat Exchanger Bypass Valve Actuator B | Module Communication | High |
| U066D | Lost Communication With Charge Air Cooler Temperature Sensor Bank 1 | Module Communication | High |
| U066E | Lost Communication With Charge Air Cooler Temperature Sensor Bank 2 | Module Communication | High |
| U066F | Lost Communication With Low Pressure Fuel System Sensor | Module Communication | High |
| U0670 | Lost Communication With Fuel Temperature Sensor A | Module Communication | High |
| U0671 | Lost Communication With Fuel Temperature Sensor B | Module Communication | High |
| U0672 | Lost Communication With Engine Coolant Pump | ECM Communication | Critical |
| U0673 | Lost Communication With Ion Sense Module | Module Communication | High |
| U0674 | Lost Communication With Wastegate Position Sensor B | Module Communication | High |
| U0675 | Lost Communication With Turbocharger/Supercharger Speed Sensor A | Module Communication | High |
| U0676 | Lost Communication With Fuel Level Sensor A | Module Communication | High |
| U0677 | Lost Communication With Fuel Level Sensor B | Module Communication | High |
| U0678 | Lost Communication With Fuel Level Sensor C | Module Communication | High |
| U0679 | Lost Communication With Transmission Fluid Pressure Sensor/Switch A | TCM Communication | Critical |
| U067A | Lost Communication With Transmission Fluid Pressure Sensor/Switch B | TCM Communication | Critical |
| U067B | Lost Communication With Engine Disconnect Clutch Pressure Sensor | ECM Communication | Critical |
| U067C | Lost Communication With Fan 3 | Module Communication | High |
| U067D | Lost Communication With Fan 4 | Module Communication | High |
| U067E | Lost Communication With Exhaust Pressure Control Valve B Sensor/Switch | Module Communication | High |
| U067F | Lost Communication With Barometric Pressure Sensor A | Module Communication | High |
| U0680 | Lost Communication With Barometric Pressure Sensor B | Module Communication | High |
| U0681 | Lost Communication With Throttle/Pedal Position Sensor/Switch D | Module Communication | High |
| U0682 | Lost Communication With Throttle/Pedal Position Sensor/Switch E | Module Communication | High |
| U0683 | Lost Communication With Throttle/Pedal Position Sensor/Switch F | Module Communication | High |
| U0684 | Lost Communication With Catalyst Temperature Bank 1 Sensor 1 | Module Communication | High |
| U0685 | Lost Communication With Catalyst Temperature Bank 1 Sensor 2 | Module Communication | High |
| U0686 | Lost Communication With Catalyst Temperature Bank 2 Sensor 1 | Module Communication | High |
| U0687 | Lost Communication With Catalyst Temperature Bank 2 Sensor 2 | Module Communication | High |
| U0688 | Lost Communication With Throttle Position Sensor/Switch G | Module Communication | High |
| U0689 | Lost Communication With Turbocharger/Supercharger B Temperature Sensor | Module Communication | High |
| U068A | Lost Communication With Barometric Pressure Sensor C | Module Communication | High |
| U068B | Lost Communication With Turbocharger/Supercharger Inlet Pressure Sensor A | Module Communication | High |
| U068C | Lost Communication With Turbocharger/Supercharger Inlet Pressure Sensor B | Module Communication | High |
| U068D | Lost Communication With EGR Temperature Sensor A | Module Communication | High |
| U068E | Lost Communication With EGR Temperature Sensor B | Module Communication | High |
| U068F | Lost Communication With EGR Temperature Sensor C | Module Communication | High |
| U0690 | Lost Communication With EGR Temperature Sensor D | Module Communication | High |
| U0691 | Lost Communication With Exhaust Pressure Sensor A | Module Communication | High |
| U0692 | Lost Communication With Exhaust Pressure Sensor B | Module Communication | High |
| U0693 | Lost Communication With Humidity Sensor | Module Communication | High |
| U0694 | Lost Communication With Hybrid/EV Battery Pack Coolant Pump A | EV/Hybrid | Critical |
| U0695 | Lost Communication With Hybrid/EV Battery Pack Coolant Pump B | EV/Hybrid | Critical |
| U0696 | Lost Communication With Particulate Filter Pressure Sensor C | Module Communication | High |
| U0697 | Lost Communication With Particulate Filter Pressure Sensor D | Module Communication | High |
| U0698 | Lost Communication with Coolant Pump “E” | Module Communication | High |
| U0699 | Lost Communication with Coolant Pump “F” | Module Communication | High |
| U069A | Lost Communication With Exhaust Gas Temperature Sensor Bank 1 Sensor 3 | Module Communication | High |
| U069B | Lost Communication With Exhaust Gas Temperature Sensor Bank 1 Sensor 4 | Module Communication | High |
| U069C | Lost Communication With Exhaust Gas Temperature Sensor Bank 2 Sensor 3 | Module Communication | High |
| U069D | Lost Communication With Exhaust Gas Temperature Sensor Bank 2 Sensor 4 | Module Communication | High |
| U069E | Lost Communication with Coolant Heater A | Module Communication | High |
| U069F | Lost Communication With Exhaust Pressure Sensor C | Module Communication | High |
| U0901 | Invalid Data from Ion Sense Module | Data Integrity | High |
| U1000 | CAN Communication Bus Fault | CAN Bus | High |
| U1001 | Lost Communication Between Modules | CAN Bus | High |
| U1002 | SCP (J1850) Invalid or Missing Data for Primary Id | CAN Bus | Medium |
| U1003 | SCP (J1850) Invalid or Missing Data for Primary Id | CAN Bus | Medium |
| U1004 | SCP (J1850) Invalid or Missing Data for EEC Programming | CAN Bus | Medium |
| U1005 | SCP (J1850) Invalid or Missing Data for EEC Programming | CAN Bus | Medium |
| U1006 | SCP (J1850) Invalid or Missing Data for Primary Id | CAN Bus | Medium |
| U1007 | SCP (J1850) Invalid or Missing Data for Primary Id | CAN Bus | Medium |
| U1008 | SCP (J1850) Invalid or Missing Data for Engine Torque | CAN Bus | Medium |
| U1009 | SCP (J1850) Invalid or Missing Data for Engine Torque | CAN Bus | Medium |
| U1010 | SCP (J1850) Invalid or Missing Data for Engine Air Intake | CAN Bus | Medium |
| U1011 | SCP (J1850) Invalid or Missing Data for Engine Air Intake | CAN Bus | Medium |
| U1012 | SCP (J1850) Invalid or Missing Data for Primary Id | CAN Bus | Medium |
| U1013 | SCP (J1850) Invalid or Missing Data for Primary Id | CAN Bus | Medium |
| U1014 | SCP (J1850) Invalid or Missing Data for Primary Id | CAN Bus | Medium |
| U1015 | SCP (J1850) Invalid or Missing Data for Primary Id | CAN Bus | Medium |
| U1016 | Communication Bus Error | CAN Bus | Medium |
| U1017 | SCP (J1850) Invalid or Missing Data for Primary Id | CAN Bus | Medium |
| U1018 | SCP (J1850) Invalid or Missing Data for Throttle | CAN Bus | Medium |
| U1019 | SCP (J1850) Invalid or Missing Data for Throttle | CAN Bus | Medium |
| U1020 | SCP (J1850) Invalid or Missing Data for Air Conditioning Clutch | CAN Bus | Medium |
| U1021 | SCP (J1850) Invalid or Missing Data for Air Conditioning Clutch | CAN Bus | Medium |
| U1022 | SCP (J1850) Invalid or Missing Data for Primary Id | CAN Bus | Medium |
| U1023 | SCP (J1850) Invalid or Missing Data for Primary Id | CAN Bus | Medium |
| U1024 | SCP (J1850) Invalid or Missing Data for Primary Id | CAN Bus | Medium |
| U1025 | SCP (J1850) Invalid or Missing Data for Primary Id | CAN Bus | Medium |
| U1026 | SCP (J1850) Invalid or Missing Data for Engine RPM | CAN Bus | Medium |
| U1027 | SCP (J1850) Invalid or Missing Data for Engine RPM | CAN Bus | Medium |
| U1028 | SCP (J1850) Invalid or Missing Data for Primary Id | CAN Bus | Medium |
| U1029 | SCP (J1850) Invalid or Missing Data for Primary Id | CAN Bus | Medium |
| U1030 | SCP (J1850) Invalid or Missing Data for Experimental #1 | CAN Bus | Medium |
| U1031 | SCP (J1850) Invalid or Missing Data for Experimental #1 | CAN Bus | Medium |
| U1032 | SCP (J1850) Invalid or Missing Data for Primary Id | CAN Bus | Medium |
| U1033 | SCP (J1850) Invalid or Missing Data for Primary Id | CAN Bus | Medium |
| U1034 | SCP (J1850) Invalid or Missing Data for Primary Id | CAN Bus | Medium |
| U1035 | SCP (J1850) Invalid or Missing Data for Primary Id | CAN Bus | Medium |
| U1036 | SCP (J1850) Invalid or Missing Data for Wheels | CAN Bus | Medium |
| U1037 | SCP (J1850) Invalid or Missing Data for Wheels | CAN Bus | Medium |
| U1038 | SCP (J1850) Invalid or Missing Data for Primary Id | CAN Bus | Medium |
| U1039 | SCP (J1850) Invalid or Missing Data for Primary Id / Vehicle Speed | CAN Bus | Medium |
| U1040 | Lost Communication with ABS | ABS Communication | Critical |
| U1041 | Lost Communication with Electronic Brake Module | Brake Module | Critical |
| U1042 | SCP (J1850) Invalid or Missing Data for Traction Control | CAN Bus | Medium |
| U1043 | SCP (J1850) Invalid or Missing Data for Traction Control | CAN Bus | Medium |
| U1044 | SCP (J1850) Invalid or Missing Data for Traction Motor | CAN Bus | Medium |
| U1045 | SCP (J1850) Invalid or Missing Data for Traction Motor | CAN Bus | Medium |
About Network Codes
This page lists all 1,532 OBD-II diagnostic trouble codes classified under the Network category. These codes are stored by your vehicle's onboard computer when a sensor detects a malfunction in the network system. Each code begins with a letter indicating the system (P for Powertrain, B for Body, C for Chassis, U for Network) followed by four digits that identify the specific fault.
When your check engine light comes on, an OBD-II scanner reads these stored codes to help pinpoint the problem. Generic codes (where the second digit is 0) follow the SAE J2012 standard and mean the same thing on every vehicle. Manufacturer-specific codes (where the second digit is 1) may have different meanings depending on the vehicle brand.
Click any code in the table above to see its full description, possible causes, common symptoms, and step-by-step repair guidance. Use the search box to quickly find a specific code within this category.