Hello all,
Im trying to troubleshoot a "Service Charging System Now" error. I've had this issue a year ago and the dealer fixed a faulty wire in the 3 pin alternator harness that was causing the issue....but they charged me $800 to diagnose the issue and it wasn't covered by warranty (62,000kms on the truck at the time). This time the issue came as an intermittent code and is now on all of the time. P0626 and p065B.

Here it goes..(using ForScan to diagnose)
Genmon is stuck at 100%
Gencmd is at a steady 65% and does not pulse
VPWR (running) is 14.63v
battery voltage is 14.69 running and 11.9-12.2 off (newer battery)

Ive pulled apart the repair the dealership did and to my surprise they actually did a nice job (harness repair below the battery box beside the frame). I've also inspected the wiring near the 3 pin connector on the alternator...all seems well.

Where would you guys suggest to focus my efforts in diagnosing this issue?

Would the GENmon signal being at 100% represent a grounded wire or generator regulator issue?

 

https://www.obd-codes.com/p0626

have you seen this?

 

You have the same problem over again.
Both codes refer to the generator control circuit lead is open.
All you need now it to locate the area and fix it right.
Good luck.

 

Finally had a chance to get into it. Genmon circuit open. Found the damaged wire 4" below the plastic harness holder on the frame below the battery box( 12" away from the last break on the Gencmd circuit). I armored the harness heavily with loom and thick harness tape. Really fun to get to with a Rough Country front cross member.

 

Great to hear you found the cause.
A testament to the codes >don't tell a lie<, in this case.
There are only three coded dedicated to the Alternator.
Always go with the complete description of any code.
Good luck.