As promissed here are the codes that I was given for my Nissan Sentra "service engine soon" light.
There are also recalls posted on Nissans sight that may prevent this from occuring. You may want to check this out as well.
Here are the codes.
P1111 - INTAKE AIR TEMPERATURE (IAT) SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE
P1131 - LACK OF HO2S SWITCH - SENSOR INDICATES LEAN
P1140 - WATER IN FUEL CONDITION