43880 - SERVICE UPDATE. FOR VEHICLES EQUIPPED WITH A START/STOP ENGINE CONTROL OPTION (RPO KL9), THE SYSTEM LEVEL INTERACTIONS RELATED TO THE TRANSITION OF RUN/CRANK AND ACCESSORY INPUTS TO THE ENGINE CONTROL MODULE (ECM) DURING A CRANK EVENT ARE COMPROMISED. THIS RESULTS IN COMMUNICATION ISSUES BETWEEN THE ECM AND THE INTELLIGENT BATTERY SENSOR. THE CHECK ENGINE LIGHT WILL ILLUMINATE AND THE START/STOP SYSTEM IS SUSPENDED WHILE THE FAULT IS ACTIVE, RESULTING IN DEGRADED FUEL ECONOMY. DEALERS ARE TO REPROGRAM THE ENGINE CONTROL MODULE.
