Jim_B Posted July 1, 2023 Report Share Posted July 1, 2023 We have a 2008 Ford Edge 3.5 SEL AWD that has almost 200k miles on it. Been great, the battery light just came on yesterday with the temps in the 100's and thought it may be the battery as the heat and age of the battery, (which was over 5 years old). Replaced it and the battery light still comes on. It is definitely something being detected as it is exactly 30 seconds after start up, every time. Ran Forscan on it and got a P0625 - Generator Field Terminal Circuit Low. But all the voltages look decent. Even the percentage of GENCMD is at 53% so it is commanding it to charge. I am pointing to the alternator but before spending $300+ on a NEW one, wanted to pick other peoples brains if you had similar experiences. I have added some screen grabs out of Forscan for reference. Any help would be greatly appreciated! Quote Link to comment Share on other sites More sharing options...
Jim_B Posted July 1, 2023 Author Report Share Posted July 1, 2023 (edited) Just a follow up, did some pin testing and the 3 pins on the alternator to ground read 1- 2.23M ohms, 2 - 157.4k ohms, 3 - 2.42M ohms. Looking on line a lot say it should be the same across the board or in the Meg ohms Edited July 1, 2023 by Jim_B Quote Link to comment Share on other sites More sharing options...
Haz Posted July 1, 2023 Report Share Posted July 1, 2023 Welcome to the Forum, Jim_B ! These Charging System references may be helpful... Document download links> Charging System - Principles of Operation - 2008 Edge Workshop Manual.pdf Charging System Pinpoint Test D - Diagnosis and Testing - 2008 Edge Workshop Manual.pdf Charging System Wiring Diagram - 2008 Edge.pdf Generator - Connector C102A Details - 2008 Edge.pdf Powertrain Control Module - Connector C175B Details - 2008 Edge.pdf Powertrain Control Module - Connector C175B Location - 2008 Edge.pdf Powertrain Control Module (PCM) - Removal and Installation - Reference For PCM Location - 2008 Edge Workshop Manual.pdf Good luck! 2 Quote Link to comment Share on other sites More sharing options...
DILLARD000 Posted July 2, 2023 Report Share Posted July 2, 2023 (edited) @Jim_B Above OBD2 info is good, but have you inspected+cleaned+tightened the connections at Battery & MegaFuse & AlternatorPower+Control & Starter & Grounds, then done a basic VoltMeter check? * Volts@BatteryTerminals with KeyOffEnginOff should be >12.2v. If lower, put a Charger on the Battery for 4+ hours, then check again. Battery should hold a charge at least a week without fading. * Volts@BatteryTerminals with KeyOnEnginIdling should be >14v@ColdStart then decreasing to >13.5v@WarmUp. If lower, then Alternator is suspect. Hopefully this helps. PS: In my 2008 FordEdgeAWD, over the years have upgraded Battery from Stock Size36R 650cca to a SizeH6 730cca (the largest physical size that would fit in the stock BatteryTray), & upgraded BatteryTerminals from Stock to 4BoltBrass Lugs (tired of constantly cleaning+tightening skimpy stock Terminals). Edited July 2, 2023 by DILLARD000 1 Quote Link to comment Share on other sites More sharing options...
Jim_B Posted July 4, 2023 Author Report Share Posted July 4, 2023 I ended up buying a new not reman alternator and put it in today and everything is back to normal. All the voltages looked good and was charging but just no signal back to the PCM. Put the new alt in and all the communication with the PCM was restored and light stayed off. Thanks for all the info. 3 1 Quote Link to comment Share on other sites More sharing options...
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