P0657 — Actuator Supply Voltage A Circuit/Open

P0657: Actuator Supply Voltage A Circuit/Open — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

Actuator Supply Voltage A Circuit/Open. Basic catalogue definition; diagnostic details have not yet been reviewed.

Affected system: Powertrain

Symptoms

  • The malfunction indicator may light up.
  • Acceleration or shifting may be affected, depending on the actuator supplied by circuit A.

Possible causes

  • An open wire or poor connector may interrupt actuator supply voltage A.
  • Corrosion, damaged wiring or a poor ground may affect this circuit.
  • A connected actuator or controller fault is possible after electrical checks.

What to check

  • Read companion codes and identify supply circuit A in the vehicle wiring diagram.
  • Inspect the circuit's connectors, wiring and grounds.
  • Check supply voltage and continuity according to manufacturer instructions before replacing modules.

Also written as: P0657-00, P065700, PO657 (some scan tools add the fault-type byte, e.g. -00).