hello to all
Just replaced my engine on a 2005 F150 lariat. Installed a motorcraft 5.4 triton and now cant get the check charging system message to go away. replaced the alternator and battery and all is working fine, however still the message to check the system. Anyone have any ideas what to do? Mechanics i talk to dont seem to like the 3 valve 5.4. 7k later and 3 months waiting, i'm getting quite frustrated

 

... check all your grounds.....like motor to tranny...motor to engine... motor to front clip... im betting you have not hooked these back up...... make sure there are clean surfaces were the ground wires or fround straps are...
Hope this helps

 

The alternator (generator as called in the factory wiring books) uses 3 fusable links (all in parallel) located in a small rectangular box next to the battery. Follow the battery positive post to the alternator; you'll see this boc with the fusable links. Ohm all three of them to verify non are open. Since you mention that the alternator is indeed charging(?), I'll assume you are seeing over 14 volts off idle as it's output.

Here is a link to another simular trouble I posted on:

https://www.f150forum.com/f4/alterna...y-light-65219/

I identified two additional wires from the alternator to the PCM that "monitors" the charge output. Check these for good continuity as well. Read the contents of the link to identify the two wires from the alternator to the PCM.

And checking all grounds is also a great idea.