OBD-II code · Network
U04B4 Invalid Data Received From Brake Blending Actuator
A receiving module detected implausible data from the brake blending actuator (manages mix of regen + friction braking on hybrids/EVs). Pressure command vs. actual fails plausibility checks and is rejected.
Is it safe to drive with U04B4?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyModule internal fault or sensor input drift
- PossibleSoftware version mismatch after replacement
- Less likelyGateway module routing CAN messages incorrectly
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–5 h
- Emissions test
- Usually unaffected
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Brake Blending Actuator
Related codes
- U04B1Invalid Data Received From Battery Monitor Module
- U04B2Invalid Data Received From Particulate Matter Sensor B
- U04B3Invalid Data Received From Planetary Gear Set Control Module
- U04B5Invalid Data Received From Brake System Control Module B
- U04B6Invalid Data Received From Catalyst Heater Control Module
- U04BAInvalid Data Received From Switch Input Module A
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.