خلل برمجية الوحدة يستلزم تحديثًا

A control module misbehaving because of its programming rather than its hardware — a bug in shipped logic, an edge case the calibration never anticipated, or two modules running versions that disagree with each other.

The tell is a fault with no physical evidence: self-check failures on modules whose supply, earth and wiring all test clean, especially when internet searches show the same code clustering on one model and year. Manufacturers fix these with reflashes, and several have covered them under service campaigns — so checking for open campaigns and technical bulletins by chassis number belongs early in any module diagnosis, being free and occasionally decisive. The expensive mistake this cause exists to prevent: replacing a module to cure the software it shipped with, then programming the replacement with the same software.