Fault Codes/Discovery Energy, LLC (Rehlko)/P0686Discovery Energy, LLC (Rehlko)P0686WarningGeneralWhat This Code MeansP0686Possible Causes•Problem with the power control relay circuitSuggested Actions1Check power control relay and leads2While the engine is running, check for high system voltage at the battery, alternator, and the ECM power input pinRelated Discovery Energy, LLC (Rehlko) Fault CodesP0687P1518 3464 13P0659P1519 3464 13P0658P1609P0657P2100P0653P2102P0643P2103Browse all Discovery Energy, LLC (Rehlko) fault codes→ASK RUDY ABOUT THIS FAULTGet a diagnosis walkthrough for P0686 on your specific Discovery Energy, LLC (Rehlko) unit — cited to the OEM manual, not a forum guess.Your question about P0686GET THE ANSWERFree account required — we'll bring your question with you.