P0657 FIAT Actuator Supply Voltage A Circuit Open

Possible causes

– Faulty Engine Control Module (ECM)
– ECM harness is open or shorted
– ECM circuit poor electrical connection
– ECM Programming

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P0657 FIAT Description

The Transmission Control Moduel (TCM) has detected a voltage supply fault to the hydraulic control unit