Fix P0625: Mechanic’s solutions that WORKED

The code P0625: Generator Field/F Terminal Circuit Low points out a fault in the generator field circuit, typically indicating low voltage output from the alternator, which can hinder the vehicle’s charging system.

P0625 quick overview

Meaning	P0625: Generator Field/F Terminal Circuit Low
Is it serious?	Yes, it can lead to vehicle power issues and should be addressed promptly.
Possible causes	– Faulty alternator – Poor battery condition – Bad connections in the charging system
How to diagnose?	Check Alternator: Ensure it’s an OEM part and functioning properly. Inspect Battery: Test the battery’s health and connections. Conduct Voltage Drop Test: Look for voltage drops in the system.

How to fix P0625 – learn from mechanics

I looked into P0625 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Ford

Vehicle Information:
2011 Ford F-150 XL 5.0L

Issue + Repair History:
Charging indicator and battery light on. Replaced battery, still faced issues. Found fault codes PO65B and PO625.

Suggestions to Fix Issue:

• Check alternator harness pin fitment.
• Reprogram BCM for battery saver mode.
• Reset battery monitor.
• Check for chafing wires near the crank dampener.

Final Fix:
Located and repaired an open circuit on the grey/red wire going to the back of the alternator. Reinstalled the original alternator, resolving the issue

Case #2: Ford

Vehicle Information:
2007 Ford Focus SES 2.0L

Issue + Repair History:

• Installed new battery and aftermarket alternator. Battery light on, high voltage reading (15.1 volts), and P0625 code stored.

Suggestions to Fix Issue:

• Check command and signal wires from PCM.
• Use a Motorcraft alternator as recommended for Ford vehicles.

Final Fix:
Replaced with a Motorcraft brand alternator from the Ford dealer, resolving the issue with a stable 14.3 volts and no battery light.

Case #3: Cadillac

Vehicle Information:
2005 Cadillac SRX 4.6L

Issue + Repair History:
Changed alternators with no success. Problem arose after valve cover gasket repair.

Suggestions to Fix Issue:

• Use OEM alternator.
• Check all modules for DTCs with a Tech2.
• Inspect harness for oil saturation.
• Verify ground cable condition.

Final Fix:
Identified and repaired a partially frayed wire at the 2-wire connector, resolving the issue.

Case #4: Ford

Vehicle Information:
2014 Ford Explorer XLT 3.5L

Issue + Repair History:
Intermittent charging system warning and loss of power steering. P0625 code found.

Suggestions to Fix Issue:

• Check belt tension and condition.
• Monitor GEN_MON PID in PCM and conduct wiggle tests on the wiring harness.
• Consider possible issues with the alternator brushes.

Final Fix:
Installed a remanufactured alternator which resolved the issue; the original had a stuck brush and a darkened slip ring.

Case #5: Hyundai

Vehicle Information:
2010 Hyundai Elantra SE 2.0L

Issue + Repair History:
Intermittent charging, codes like P0625 indicating charging system problems. Voltage drop noted at idle.

Suggestions to Fix Issue:

• Use OEM alternator.
• Check battery and terminals.
• Perform voltage drop tests, especially from the battery to the fuse box.

Final Fix:
Replaced with a remanufactured OEM alternator, fixing the issue. Brushes were found stuck and slip rings darkened.

Advice	Brief Description of Diagnostic Step
Use OEM Alternator	Prefer original equipment manufacturer parts for replacements.
Check Battery	Test the battery’s health and its connections.
Perform Voltage Drop Test	Test for voltage drops in the system, especially in charging cables and connectors.