U0011moderate severityNetwork
Control Module Communication Bus A Low
on 2026 Mazda Mazda3 2.0L I4 · FWD
What this code means
The voltage on communication bus A is too low, disrupting data sharing between modules. Modules may not talk to each other properly.
Symptoms
- Multiple warning lights on
- Modules not responding
- Erratic gauge behavior
Common causes
- Shorted bus A wiring to ground
- Faulty control module
- Corroded or loose connectors
- Damaged wiring harness
Diagnostic steps
- Scan all modules for U-codes
- Inspect bus A wiring for shorts
- Measure bus A voltage with meter
- Isolate modules to find fault
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Autel MaxiCOM MK808S →
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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