U0046high severityNetwork
Vehicle Communication Bus B Off
on 2017 Mazda MX-5 Miata 2.0L I4 · RWD
What this code means
CAN bus B is completely offline. No communication on the secondary CAN bus.
Symptoms
- Secondary systems inoperative
- Body control functions down
- Climate control offline
- Entertainment system not communicating
Common causes
- CAN bus B wiring shorted or open
- Bus B termination resistor failure
- Module pulling down bus B
- Major connector failure
Diagnostic steps
- Measure bus B resistance
- Check bus B voltage levels
- Isolate bus B segments
- Inspect bus B connectors
Repair notes
Complete bus B failure requires systematic wiring diagnosis.
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