P0659 Actuator Supply Voltage A Circuit High

P0659 indicates a high condition on Actuator Supply Voltage A circuit. The shared actuator supply is above the expected range or being backfed.

Code details

Generic OBD-II · P0

System: Computer
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not keep operating actuators on an over-voltage supply until the source of the high voltage is found.

Symptoms of P0659

Check-engine light, sometimes with several unrelated codes at once.
Warning lights, a no-start, or intermittent electrical faults.
Communication or module-reset problems on a scan tool.

Common causes of P0659

Low battery voltage, poor grounds, corroded connectors, or blown fuses.
Wiring or network (CAN bus) faults between modules.
A module software/programming issue, or rarely a failed controller.

Useful checks before replacing parts

Check actuator supply A voltage, relay status, fuse feed, affected actuator commands, freeze-frame data, and other high-voltage supply codes.
Inspect for short-to-voltage faults, stuck relays, open grounds, crossed circuits, aftermarket wiring, connector corrosion, and backfed actuator branches.
Disconnect branches of the supply circuit to identify whether a relay, harness, actuator, or module output is holding voltage high.

Related OBD-II codes

These nearby computer entries can help compare wording and pin down the fault area.