Error code
OBD2 U0004
OBD2U0004
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.
What it means
High Speed CAN Communication Bus (Low).
Severity
highDriving may be possible but could lead to further damage and safety risks.
Summary
U0004 indicates an issue with the high-speed CAN (Controller Area Network) communication bus, specifically low voltage on the positive side of the bus.
Common Causes
- Loose or corroded connectors in the high-speed CAN network
- Faulty CAN transceiver module
- Power supply issues affecting the CAN bus
Fixes
FAQ
What does U0004 mean?
U0004 indicates a problem with the high-speed CAN communication bus, specifically low voltage on the positive side of the bus.
How serious is this issue?
This issue is considered serious as it affects critical vehicle systems and can lead to further damage if not addressed.
Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.
More OBD2 codes
- U0001High Speed CAN Communication Bus
- U0002High Speed CAN Communication Bus (Performance)
- U0003High Speed CAN Communication Bus (Open)
- U0005High Speed CAN Communication Bus (High)
- U0006High Speed CAN Communication Bus (Open)
- U0007High Speed CAN Communication Bus (Low)
- U0008High Speed CAN Communication Bus (High)
- U0009High Speed CAN Communication Bus (shorted to Bus)
- U0010Medium Speed CAN Communication Bus
- U0011Medium Speed CAN Communication Bus (Performance)
- U0012Medium Speed CAN Communication Bus (Open)
- U0013Medium Speed CAN Communication Bus (Low)