Ecu pin out diagram

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Nikko84

Nikko84

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Alternator. My battery light is on and it says Check Charging System in the info screen. So I was going to check the three wires going to the pcm from the plug.
 

Hamfisted

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How old is your alternator ? With the engine at idle, what voltage are you reading at the battery? Should be 13.5 - 14.0 volts.
If you recently replaced the alternator, did you use a 110 amp alternator from NAPA or Motorcraft ? Don't use one from O-Reilly's or Advance Auto, they're garbage. Don't install a 135 amp alternator unless your Expedition came from the factory with navigation. The "Check Charging System" message is common when people install a 135 amp alternator when the PCM expects to see a 110 amp alternator.


2003 Expedition Alternators at Rock Auto






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  • 2003+ Expedition - Charging Circuit.pdf
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