Fault Codes/Winco/SPN 4765 FMI 4WincoSPN 4765 FMI 4WarningCoolingWhat This Code MeansSubstitute value is taken for Oxi Cat temperature upstream sensorPossible Causes•Defect in the electrical signal of the Oxi Cat temperature upstream sensorRelated Winco Fault CodesUNDERSPEEDSPN 4765 FMI 3SPN 174 FMI 4SPN 174 FMI 3SPN 172 FMI 4SPN 172 FMI 3SPN 168 FMI 4SPN 168 FMI 3SPN 166 FMI 14SPN 166 FMI 2OVERSPEEDGENERATOR UNDER VOLTAGEBrowse all Winco fault codes→ASK RUDY ABOUT THIS FAULTGet a diagnosis walkthrough for SPN 4765 FMI 4 on your specific Winco unit — cited to the OEM manual, not a forum guess.Your question about SPN 4765 FMI 4GET THE ANSWERFree account required — we'll bring your question with you.