U0128critical severityNetwork
Lost Communication with Brake Boost Control Module
on 2019 Audi A6 3.0L V6 TFSI · AWD
What this code means
Cannot communicate with the power brake booster control module on vehicles with electric brake boost.
Symptoms
- Brake pedal feels hard
- Brake boost warning light
- Increased stopping distance
- Brake assist not available
Common causes
- Electric brake booster module failure
- CAN bus wiring
- Module power loss
- Fuse blown
- Brake booster motor failure
Diagnostic steps
- Check brake booster module fuse
- Test module power and ground
- Check CAN wiring
- Test brake booster motor
- Check brake fluid level
Repair notes
Safety critical. Brakes still function but with no power assist. Check fuses and power supply.
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Other Network codes on this vehicle
00003
Control Module - Defective
01304
Radio - No Communication
01312
Powertrain Data Bus - Defective
01314
Engine Control Module (ECM) - no communications
01315
Transmission Control Module (TCM) - No Communication
01316
ABS Control Module - No Communication
01317
Instrument Cluster Control Module (J285) - No Communication
01318
Immobilizer Control Module - No Communication
01321
Airbag Control Module - No Communication
U0001
High Speed CAN Communication Bus