Fault Codes/Rehlko/1239 0Rehlko1239 0UnclassifiedFuelWhat This Code MeansFuel leak; Supply voltage out of rangePossible Causes•Common rail leakage•Common rail leakage sensorRelated Rehlko Fault Codes1239 111239 31662 0DEF QUALITY ALERT661 8DERATE WARNING661 5DTC661 4K0691661 3KD27V12Browse all Rehlko fault codes→ASK RUDY ABOUT THIS FAULTGet a diagnosis walkthrough for 1239 0 on your specific Rehlko unit — cited to the OEM manual, not a forum guess.TRY IT FREE