U0056low severityNetwork
LIN Bus B Communication Performance
on 2021 Mazda Mazda3 2.5L I4 · FWD
What this code means
Communication on LIN bus B is degraded or intermittent.
Symptoms
- Specific LIN B devices intermittent
- HVAC blend door actuator issues
- Seat heater communication errors
Common causes
- LIN bus B wiring degradation
- LIN slave device fault on bus B
- High resistance in LIN B circuit
Diagnostic steps
- Check LIN bus B voltage levels
- Test LIN B wiring resistance
- Inspect LIN B device connections
- Test individual LIN B slave devices
Repair notes
Check LIN bus B wiring and slave device connections.
Other Network codes on this vehicle
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 Together
U0010
Medium Speed CAN Communication Bus