I have a code on my 2000 caddy Eldorado etc. it says 127106 service charging sys. What is the deal??

Question

check engine lite on dash says 127106 service charging sys. where do I start??

Answer 1

SERVICE CHARGING SYSTEM

This message is from the PCM which send it to the IPC (Instrument panel) by a serial line.Check the charging system,with the engine running you should have 13volts to 14 volts. If the battery is good and the charging system is good, The problem reside with the  aternator L-terminal (which is part of the alternator) Check for code if there is a P0621 and or P0622 you will need a alternator just to turn the message off.