Anti Theft Problem

Hi, I have a cadillac seville 95 and today I got a msg on the display board saying "Anti-theft problem, car may not restart". Everytime this message shows and its very frequent my volts go down to like 11.7 and the rpms just up and down without any reason. I am getting my alternator replaced, I am getting the car back tomorrow any idea if this will fix the problem or what the problem might be? Thanks alot.

Low battery voltage often causes bogus codes and warnings on these cars. After the alternator is replaced have them put the charger on the battery for a while to bring it up to full charge. If the message reoccurs post back.

The new alternator seemed to have fixed the problem:) Volts are always at 13.6 and higher now.