One problem related to ignition module has been reported for the 2007 Cadillac STS. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2007 Cadillac STS based on all problems reported for the 2007 STS.
10/27/06 multiple warning lights & refusal to exceed 40mph, due to low voltage/low amps on battery causing communication errors w mult modules, new battery installed. Summers 2008 & 2010 refusal to turn over even w keyfob in slot, towed, new battery inst. Towed July 2011 for refusal to turn over or take jump, shop found normal battery & jump successful. New keyfob 9/14/11 @my request. Towed 2/27/12 for refusal to turn over or take jump, new battery installed, remotes reprogrammed. Towed 7/3/13 for refusal to turn over or take jump, new battery installed @my request. Towed 3/4/14 for refusal to turn over or take jump, ignition system & battery ok, no explanation. Three days ago refusal to turn over despite keyfob in hand, 2minutes later it started. Wonder if 2007 cad Sts shd be included in gm delphi system recall. Getting expensive.