Have you tried pulling codes before shutting off the engine? That was the only time I saw low voltage codes. They disappeared when I turned off the engine.The only code I've ever seen was this - 1048836 - Blower Output Reduction due to Energy Management B10CE 00  - . My issues returned a couple weeks after the alternator was replaced for the 2nd time. No steering warning light or any other warning lights ever. Car runs fine otherwise.