A member over at DP posted this concerning a harness rub-thru on the LML's, similar to the LLY injector harness. It can cause a random shutdown condition:
http://gm.oemdtc.com/4212/gauge-fluctuation-various-dtcs-2011-2013-chevrolet-silverado-gmc-sierra
http://gm.oemdtc.com/4212/gauge-fluctuation-various-dtcs-2011-2013-chevrolet-silverado-gmc-sierra