Network Codes
1,532 OBD-II diagnostic trouble codes in this category.
Showing page 1 of 16 (1,532 codes total)
| Code | Description | Subsystem | Severity |
|---|---|---|---|
| U0001 | High Speed CAN Communication Bus | CAN Bus | High |
| U0002 | High Speed CAN Communication Bus Performance | CAN Bus | High |
| U0003 | High Speed CAN Communication Bus Open | CAN Bus | Critical |
| U0004 | High Speed CAN Communication Bus Low | CAN Bus | Critical |
| U0005 | High Speed CAN Communication Bus High | CAN Bus | Critical |
| U0006 | Medium Speed CAN Communication Bus | CAN Bus | High |
| U0007 | Medium Speed CAN Communication Bus Performance | CAN Bus | Medium |
| U0008 | Medium Speed CAN Communication Bus Open | CAN Bus | High |
| U0009 | Medium Speed CAN Communication Bus Low | CAN Bus | High |
| U0010 | Medium Speed CAN Communication Bus High | CAN Bus | High |
| U0011 | Medium Speed CAN Communication Bus Performance | CAN Bus | High |
| U0012 | Medium Speed CAN Communication Bus (+) Open | CAN Bus | High |
| U0013 | Medium Speed CAN Communication Bus (+) Low | CAN Bus | High |
| U0014 | Medium Speed CAN Communication Bus (+) High | CAN Bus | High |
| U0015 | Medium Speed CAN Communication Bus (-) Open | CAN Bus | High |
| U0016 | Medium Speed CAN Communication Bus (-) Low | CAN Bus | High |
| U0017 | Medium Speed CAN Communication Bus (-) High | CAN Bus | High |
| U0018 | Medium Speed CAN Communication Bus (-) shorted to Bus (+) | CAN Bus | High |
| U0019 | Low Speed CAN Communication Bus | CAN Bus | High |
| U0020 | Low Speed CAN Communication Bus Performance | CAN Bus | High |
| U0021 | Low Speed CAN Communication Bus (+) Open | CAN Bus | High |
| U0022 | Low Speed CAN Communication Bus (+) Low | CAN Bus | High |
| U0023 | Low Speed CAN Communication Bus (+) High | CAN Bus | High |
| U0024 | Low Speed CAN Communication Bus (-) Open | CAN Bus | High |
| U0025 | Low Speed CAN Communication Bus (-) Low | CAN Bus | High |
| U0026 | Low Speed CAN Communication Bus | CAN Bus | Medium |
| U0027 | Low Speed CAN Communication Bus Performance | CAN Bus | Medium |
| U0028 | Low Speed CAN Communication Bus Open | CAN Bus | Medium |
| U0029 | Vehicle Communication Bus A Performance | CAN Bus | High |
| U0030 | Vehicle Communication Bus A (+) Open | CAN Bus | High |
| U0031 | Vehicle Communication Bus A (+) Low | CAN Bus | High |
| U0032 | Vehicle Communication Bus A (+) High | CAN Bus | High |
| U0033 | Vehicle Communication Bus A (-) Open | CAN Bus | High |
| U0034 | Vehicle Communication Bus A (-) Low | CAN Bus | High |
| U0035 | Vehicle Communication Bus A (-) High | CAN Bus | High |
| U0036 | Vehicle Communication Bus A (-) shorted to Bus A (+) | CAN Bus | High |
| U0037 | Vehicle Communication Bus B | CAN Bus | High |
| U0038 | Vehicle Communication Bus B Performance | CAN Bus | High |
| U0039 | Vehicle Communication Bus B (+) Open | CAN Bus | High |
| U0040 | Vehicle Communication Bus B (+) Low | CAN Bus | High |
| U0041 | Vehicle Communication Bus B (+) High | CAN Bus | High |
| U0042 | Vehicle Communication Bus B (-) Open | CAN Bus | High |
| U0043 | Vehicle Communication Bus B (-) Low | CAN Bus | High |
| U0044 | Vehicle Communication Bus B (-) High | CAN Bus | High |
| U0045 | Vehicle Communication Bus B (-) shorted to Bus B (+) | CAN Bus | High |
| U0046 | Vehicle Communication Bus C | CAN Bus | High |
| U0047 | Vehicle Communication Bus C Performance | CAN Bus | High |
| U0048 | Vehicle Communication Bus C (+) Open | CAN Bus | High |
| U0049 | Vehicle Communication Bus C (+) Low | CAN Bus | High |
| U0050 | Vehicle Communication Bus C (+) High | CAN Bus | High |
| U0051 | Vehicle Communication Bus C (-) Open | CAN Bus | High |
| U0052 | Vehicle Communication Bus C (-) Low | CAN Bus | High |
| U0053 | Vehicle Communication Bus C (-) High | CAN Bus | High |
| U0054 | Vehicle Communication Bus C (-) shorted to Bus C (+) | CAN Bus | High |
| U0055 | Vehicle Communication Bus D | CAN Bus | High |
| U0056 | Vehicle Communication Bus D Performance | CAN Bus | High |
| U0057 | Vehicle Communication Bus D (+) Open | CAN Bus | High |
| U0058 | Vehicle Communication Bus D (+) Low | CAN Bus | High |
| U0059 | Vehicle Communication Bus D (+) High | CAN Bus | High |
| U0060 | Vehicle Communication Bus D (-) Open | CAN Bus | High |
| U0061 | Vehicle Communication Bus D (-) Low | CAN Bus | High |
| U0062 | Vehicle Communication Bus D (-) High | CAN Bus | High |
| U0063 | Vehicle Communication Bus D (-) shorted to Bus D (+) | CAN Bus | High |
| U0064 | Vehicle Communication Bus E | CAN Bus | High |
| U0065 | Vehicle Communication Bus E Performance | CAN Bus | High |
| U0066 | Vehicle Communication Bus E (+) Open | CAN Bus | High |
| U0067 | Vehicle Communication Bus E (+) Low | CAN Bus | High |
| U0068 | Vehicle Communication Bus E (+) High | CAN Bus | High |
| U0069 | Vehicle Communication Bus E (-) Open | CAN Bus | High |
| U0070 | Vehicle Communication Bus E (-) Low | CAN Bus | High |
| U0071 | Vehicle Communication Bus E (-) High | CAN Bus | High |
| U0072 | Vehicle Communication Bus E (-) shorted to Bus E (+) | CAN Bus | High |
| U0073 | Control Module Communication Bus Off | CAN Bus | High |
| U0074 | Control Module Communication Bus B Off | CAN Bus | High |
| U0075 | Control Module Communication Bus C Off | CAN Bus | High |
| U0076 | Control Module Communication Bus D Off | CAN Bus | High |
| U0077 | Control Module Communication Bus E Off | CAN Bus | High |
| U0078 | Control Module Communication Bus F Off | CAN Bus | High |
| U0079 | Control Module Communication Bus G Off | CAN Bus | High |
| U007A | Control Module Communication Bus H Off | CAN Bus | High |
| U007B | Control Module Communication Bus I Off | CAN Bus | High |
| U007C | Control Module Communication Bus J Off | CAN Bus | High |
| U007D | Control Module Communication Bus K Off | CAN Bus | High |
| U007E | Control Module Communication Bus L Off | CAN Bus | High |
| U007F | Control Module Communication Bus M Off | CAN Bus | High |
| U0080 | Vehicle Communication Bus F | CAN Bus | High |
| U0081 | Vehicle Communication Bus F Performance | CAN Bus | High |
| U0082 | Vehicle Communication Bus F + Open | CAN Bus | High |
| U0083 | Vehicle Communication Bus F + Low | CAN Bus | High |
| U0084 | Vehicle Communication Bus F + High | CAN Bus | High |
| U0085 | Vehicle Communication Bus F - Open | CAN Bus | High |
| U0086 | Vehicle Communication Bus F - Low | CAN Bus | High |
| U0087 | Vehicle Communication Bus F - High | CAN Bus | High |
| U0088 | Vehicle Communication Bus F - Shorted to Bus F + | CAN Bus | High |
| U0089 | Vehicle Communication Bus G | CAN Bus | High |
| U008A | Vehicle Communication Bus G Performance | CAN Bus | High |
| U008B | Vehicle Communication Bus G (+) Open | CAN Bus | High |
| U008C | Vehicle Communication Bus G (+) Low | CAN Bus | High |
| U008D | Vehicle Communication Bus G (+) High | CAN Bus | High |
| U008E | Vehicle Communication Bus G (-) Open | CAN Bus | High |
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.