Fault Codes/Rehlko/1239 11Rehlko1239 11UnclassifiedFuelWhat This Code MeansFuel leak; Supply voltage out of rangePossible Causes•Common rail leakage•Common rail leakage sensorRelated Rehlko Fault Codes1239 31DEF QUALITY ALERT1239 0DERATE WARNING662 0DTC661 8K0691661 5KD27V12661 4NOX FAULTBrowse all Rehlko fault codes→ASK RUDY ABOUT THIS FAULTGet a diagnosis walkthrough for 1239 11 on your specific Rehlko unit — cited to the OEM manual, not a forum guess.TRY IT FREE