U0029moderate severityNetwork
Vehicle Communication Bus B Performance
on 2003 Mazda MX-5 Miata 1.8L I4 · RWD
What this code means
CAN bus B performance is degraded with intermittent communication issues.
Symptoms
- Secondary systems intermittent
- Body control functions erratic
- Climate control glitches
Common causes
- Wiring degradation on bus B
- Module fault on bus B
- Poor splice connections
- Aftermarket device loading bus
Diagnostic steps
- Scope bus B signals
- Check bus B termination
- Inspect bus B wiring
- Isolate modules on bus B
Repair notes
Diagnose bus B wiring and termination. Check for aftermarket device interference.
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