Check Guages light and 2 fault codes!

My wife's 1993 Plymouth Voyager has about 100K miles. Occasionally the Check Guages light comes on and the engines instantly dies. This usually happens when slowing or when slowing and turning. Nothing else consistant about when it happens. I ran the fault codes and came up with 12 and 25. 12 is "Fault in Standby Memorey Circuit" and 25 is "Fault in AIS Control Circuit." Any advice or help would be appreciated.