Fault Codes/Discovery Energy, LLC (Rehlko)/P2188Discovery Energy, LLC (Rehlko)P2188ErrorGeneralWhat This Code MeansSystem Rich at IdlePossible Causes•Problem with the closed-loop feedback controlSuggested Actions1Check for misfires2Check fuel quality3Check fuel pressure regulator and outlet pressure4Check for exhaust leaks5Check for intake manifold leaks6Troubleshoot the HEGO sensor for bad leads. Refer to the Heated Exhaust Gas Oxygen (HEGO) Sensor Troubleshooting section7Replace the HEGO sensor. Refer to the Heated Exhaust Gas Oxygen Sensor (HEGO) sectionRelated Discovery Energy, LLC (Rehlko) Fault CodesP2191P2192P2187P2243P2178P2305P2177P2306P2135P2307P2119P2308Browse all Discovery Energy, LLC (Rehlko) fault codes→ASK RUDY ABOUT THIS FAULTGet a diagnosis walkthrough for P2188 on your specific Discovery Energy, LLC (Rehlko) unit — cited to the OEM manual, not a forum guess.Your question about P2188GET THE ANSWERFree account required — we'll bring your question with you.