Lost Communication With Brake System Control Module B

Where it lives

For U01B4, start at the module the description names.

Check these first

• A faulty brake system control module B
• A software or calibration error in module B
• Corroded or damaged connector pins at module B
• Loss of power or ground to module B
• Module B not communicating over the CAN bus

What to do next

1. Inspect the module B connector pins for corrosion
2. Check power and ground at brake system control module B
3. Verify module B communicates on the CAN bus
4. Reprogram the control module if calibration is the cause
5. Replace brake system control module B if it stays offline
6. Clear the code and retest

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