U0057
Vehicle Communication Bus D (+) Open
What it means
U0057 means Vehicle Communication Bus D (+) Open.
Check these first
- An open in the bus D (+) wire between two modules
- A broken or backed out pin at a bus D (+) connector
- A module connector not fully seated on the bus D (+) circuit
- Corrosion eating through the bus D (+) conductor
What to do next
- Read stored codes on every module that shares bus D
- Trace the bus D (+) wire end to end for an open
- Check each bus D (+) connector pin for a poor fit or backing out
- Repair or replace the open section of the bus D (+) wire
- Replace the module that stays off the bus D (+) line
- Clear the code and retest
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Updated
Generic SAE J2012 definition. Last updated 2026-10-10.