Fault Codes/Cummins/DS12CumminsDS12UnclassifiedCoolingWhat This Code MeansThe genset will not start automatically; Battery voltage too high; Battery voltage too low; Low engine coolant temperaturePossible Causes•Switch on the control is in the Not in Auto position•Battery overcharging•Poor battery•Charger failure•Engine coolant heater has malfunctionedRelated Cummins Fault CodesDS13DS14DS11DS15DS9DS16DS8DS17DS7DS20DS6DS21Browse all Cummins fault codes→ASK RUDY ABOUT THIS FAULTGet a diagnosis walkthrough for DS12 on your specific Cummins unit — cited to the OEM manual, not a forum guess.TRY IT FREE