Fault Codes/Discovery Energy, LLC (Rehlko)/P1138Discovery Energy, LLC (Rehlko)P1138ErrorCoolingWhat This Code MeansHEGO Sensor OverheatPossible Causes•Problem with poor HEGO sensor performanceSuggested Actions1Check for excessive exhaust temperaturesRelated Discovery Energy, LLC (Rehlko) Fault CodesP1630P1631P0217P1632P0128P0127P0126P0125P1138 3217 31P1518 3464 13P1137P1519 3464 13Browse all Discovery Energy, LLC (Rehlko) fault codes→ASK RUDY ABOUT THIS FAULTGet a diagnosis walkthrough for P1138 on your specific Discovery Energy, LLC (Rehlko) unit — cited to the OEM manual, not a forum guess.Your question about P1138GET THE ANSWERFree account required — we'll bring your question with you.