U0128
NetworkModule Communicationcritical severityLost Communication with Brake Boost Control Module
What U0128 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
Where to start: Safety critical. Brakes still function but with no power assist. Check fuses and power supply.
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