Powertrain, generic · Computer and auxiliary outputs

P0657 Actuator Supply Voltage A Circuit/Open

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Actuator supply A is a high-side switch feeding several actuators together; its use differs by maker (Ford transmission solenoids, GM shared high-side driver, GM Europe 2.0 CDTI internal 5 V supply). P0657 is the open-circuit code; it is documented at Ford: the high-side switch of the 5R110W and 6R80 automatics feeds all shift solenoids, and the 2023 diesels split them into two supplies (P0657 and P2669), checked continuously. On a fault the solenoids are de-energised and the transmission falls back to a mechanical limp gear with maximum line pressure – harsh shifts and a single forward gear. Ford's 6.8 L V10 reports it with or without the lamp depending on the variant. GM does not use P0657 and reports opens together with ground faults under P0658.

Likely causes

Open or connector fault at the transmission pass-through connector or wire to the valve body
Damaged harness
Internal high-side switch in the engine or transmission module
Internal transmission harness

Symptoms

  • Transmission limp mode (fixed gear)
  • Harsh shifts, no upshift
  • Check engine light (depending on the variant)
  • Codes for individual shift solenoids

Repair estimate

DifficultyHardWorkshop job
Parts and labour€150–1,500
Time1–5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

actuator supply circuittransmission solenoidscontrol module

Related codes

P0658P0659P2669P0750P0973

References: law.cornell.edu, newtonnet.co.uk, fordservicecontent.com, roushcleantech.com.