P0625 Generator Field/F Terminal Circuit Low

P0625 indicates a low condition in the generator field or F terminal circuit. The controller sees field circuit voltage or feedback below the expected range.

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 install an alternator without checking field circuit voltage drop and connector condition.

Symptoms of P0625

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 P0625

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 F terminal voltage, field command, charging voltage, battery state, fuse feed, ground path, freeze-frame load, and related charging faults.
Inspect for short-to-ground faults, open power feed, damaged field wiring, alternator connector corrosion, regulator faults, weak grounds, and belt issues.
Load-test the generator while monitoring field command and output to isolate wiring, alternator, or controller faults.

Related OBD-II codes

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