P0625: Generator Field/F Terminal Circuit Low
What to do
Have the charging voltage measured before driving far. Overcharging destroys batteries quickly and can damage electronic modules, so this is worth prompt attention rather than leaving to the next service.
What this code means
The alternator field circuit is reading low — a short to ground, or a regulator holding the field on. A field held permanently energised means uncontrolled charging, so this is the version of the fault most likely to be overcharging the battery.
Measure the voltage at the battery with the engine running. Anything much above the upper end of the normal charging range is damaging the battery every minute it continues.
Likely causes
Start here
- Faulty alternator voltage regulator · moderate
- Signal wire shorted to ground · moderate
- Faulty alternator · moderate
Less common
- Corroded or loose connector · easy
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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