U0037low severityNetwork
LIN Bus A Communication Performance
on 2021 Mazda Mazda3 2.5L I4 · FWD
What this code means
Communication on LIN bus A is degraded. LIN buses connect lower-priority subsystems like seat modules, rain sensors, and mirror controls.
Symptoms
- Seat adjustment issues
- Rain sensor not responding
- Auto-dimming mirror malfunction
- Intermittent accessory faults
Common causes
- LIN bus wiring issue
- LIN master module fault
- LIN slave device failure
- Wiring resistance too high
Diagnostic steps
- Check LIN bus voltage (typically 0-12V)
- Test LIN master module
- Inspect LIN wiring for high resistance
- Check LIN slave device responses
Repair notes
LIN bus operates at lower speeds. Check wiring resistance and master module.
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