my caddy wont start

These all Caddys always have lots of DTC codes or lights on, Have them scan it again for DTC's write them down. Now, have the shop correct all the things it missed last few time its been there, Grounds? are they loose, corroded, etc...Have them do another voltage drop test on the starter circuit until they locate the high resistance on the "2 gauge wire, might as well check the output of the alternator at battery terminals again engine running! 13.4 -14.8 volts. Tell them to stop charging you $ each time your there for the same problem...Regards