If the alternator's voltage regulator is failing, it sends "invalid" energy status signals to the DME, which then ripples to the EPS module.
While the code points to the steering system, the root cause is often electrical rather than mechanical. bmw error-d52c44
The fault may disappear after restarting the car but return during heavy electrical load or when the Auto Start-Stop function engages. If the alternator's voltage regulator is failing, it
Modern BMWs are highly sensitive to voltage drops. An old battery may not provide the 13.3V to 14.9V required for stable communication between modules. bmw error-d52c44