Fault Codes/Discovery Energy, LLC (Rehlko)/D20Discovery Energy, LLC (Rehlko)D20UnclassifiedAir IntakeWhat This Code MeansAir damper indicator activeRelated Discovery Energy, LLC (Rehlko) Fault CodesP0234P0236P0237P0238EMERGENCY STOPENGINE STAD15GROUND FAULTD14HI COOL TEMP SHUTDOWND13HI COOL TEMP WARNINGBrowse all Discovery Energy, LLC (Rehlko) fault codes→ASK RUDY ABOUT THIS FAULTGet a diagnosis walkthrough for D20 on your specific Discovery Energy, LLC (Rehlko) unit — cited to the OEM manual, not a forum guess.Your question about D20GET THE ANSWERFree account required — we'll bring your question with you.