U0001 : High Speed CAN Communication Bus
U0002 : High Speed CAN Communication Bus Performance
U0003 : High Speed CAN Communication Bus (+) Open
U0004 : High Speed CAN Communication Bus (+) Low
U0005 : High Speed CAN Communication Bus (+) High
U0006 : High Speed CAN Communication Bus (-) Open
U0007 : High Speed CAN Communication Bus (-) Low
U0008 : High Speed CAN Communication Bus (-) High
U0009 : High Speed CAN Communication Bus (-) shorted to Bus (+)
U0010 : Medium Speed CAN Communication Bus
U0011 : Medium Speed CAN Communication Bus Performance
U0012 : Medium Speed CAN Communication Bus (+) Open
U0013 : Medium Speed CAN Communication Bus (+) Low
U0014 : Medium Speed CAN Communication Bus (+) High
U0015 : Medium Speed CAN Communication Bus (-) Open
U0016 : Medium Speed CAN Communication Bus (-) Low
U0017 : Medium Speed CAN Communication Bus (-) High
U0018 : Medium Speed CAN Communication Bus (-) shorted to Bus (+)
U0019 : Low Speed CAN Communication Bus
U0019 : Low Speed CAN Communication Bus
U0020 : Low Speed CAN Communication Bus Performance
U0021 : Low Speed CAN Communication Bus (+) Open
U0022 : Low Speed CAN Communication Bus (+) Low
U0023 : Low Speed CAN Communication Bus (+) High
U0024 : Low Speed CAN Communication Bus (-) Open
U0025 : Low Speed CAN Communication Bus (-) Low
U0026 : Low Speed CAN Communication Bus (-) High
U0027 : Low Speed CAN Communication Bus (-) shorted to Bus (+)
U0028 : Vehicle Communication Bus A
U0029 : Vehicle Communication Bus A Performance
OBD-I codes were manufacturer-specific and used before 1996. OBD-II codes, used in vehicles manufactured after 1996, are standardized and follow a universal coding format.
UXXXX OBD-II codes are Network diagnostic trouble codes that relate to communication issues between different control modules and the vehicle's data bus.
The letter "U" stands for User Network/Network . It indicates that the fault is related to communication issues within the vehicle's network or modules.
UXXXX codes indicate communication faults between different control modules in the vehicle. While they may not immediately affect performance, they can cause unpredictable behavior and should be investigated to prevent cascading issues.
Network (U) codes indicate communication problems between vehicle modules. Detecting these requires a high-end OBD-II scanner with full system coverage, as basic readers cannot interpret communication faults.
Some U codes are generic, but many are manufacturer-specific, meaning the exact definition may vary by vehicle brand.
Yes, with a compatible diagnostic scanner. However, clearing the code without fixing the issue may cause it to return.
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