Code result
U04B4
Invalid Data Received From Brake Blending Actuator
High severity
What it means
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?
No — stop driving
This code can put the vehicle into limp or reduced-power mode. Avoid extended driving and have the vehicle diagnosed promptly.
Most likely causes
Module internal fault or sensor input drift
highOne of the most commonly reported causes for this code — check this first.
Software version mismatch after replacement
mediumA plausible cause — test and verify before replacing parts.
Gateway module routing CAN messages incorrectly
lowLess common, but worth ruling out after the more likely causes.
Related help
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