Error code
OBD2 U0040
OBD2U0040
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.
What it means
Vehicle Communication Bus B (Low).
Severity
highDriving may be possible but could lead to further issues if not addressed.
Summary
U0040 indicates that the Vehicle Communication Bus B has low voltage, which affects data transmission between modules in this network.
Common Causes
- Low power supply to VAN data bus B
- Faulty wiring or connectors on VAN data bus B
Fixes
FAQ
What does U0040 mean?
U0040 indicates a low voltage issue on the Vehicle Communication Bus B, which can disrupt communication between vehicle modules.
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)
- U0004High Speed CAN Communication Bus (Low)
- 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)