Allison WTEC II Fault Code: 63 PID: SPN: 41 FMI: Pump/pack and a neutral general purpose input

Subcode 41 is set when the states of the calibration inputs are different for a calibration number of consecutive updates. The inputs in this case are Pump/Pack Enable and Automatic Neutral For Refuse Packer. The service display will also be turned ON if selected by calibration.