The Engine Control Module (ECM) monitors and regulates the operation of the engine’s actuators, sensors, and other components to achieve the most efficient performance from the engine.
When the P0657 OBD2 diagnostic code is set and the other related codes indicate that the ECM has encountered a malfunction in the actuator, and this condition is due to an open circuit. It should be noted that by designating it as A, the manufacturer may be referring to a particular circuit, wiring, or area, so it is necessary to consult the vehicle’s information source.