Mack Derate Fault Codes

Mack fault code P0087-00 indicates low fuel rail or fuel system pressure.

Mack fault code P009B13 generally relates to the fuel pressure relief control circuit or fuel pressure control system.

Mack fault code P103C is commonly associated with SCR/NOx conversion testing or aftertreatment performance on Mack/Volvo platforms.

Mack fault code P113000 is generally an emissions or sensor-performance fault that can contribute to derate depending on engine calibration.

Mack fault code P203A13 generally points to a DEF/reductant level sensor circuit issue.

Mack fault code P203C00 commonly indicates a low signal or circuit problem from the DEF/reductant level sensor.

Mack fault code P207F is commonly associated with reductant quality performance.

Mack fault code P20EE-00 indicates SCR NOx catalyst efficiency below threshold.

Mack fault code U029D-00 usually indicates lost communication with a NOx sensor module.

Mack fault code U029E-00 usually indicates lost communication with the other NOx sensor module in the SCR system.