Allison WTEC II Fault Code: 52 PID: SPN: 8 FMI: Offgoing C3PS test (during shift), L to N1

Main code 52 indicates a failed C3 pressure test. L?N1 shift

When a shift is commanded and C3 is the offgoing clutch, the ECU expects the C3 pressure switch to open within a period of time after the shift is commanded. If the ECU does not see the switch open, it assumes C3 has not released. If conditions for a shift exist, the shift is retried. If the
C3 pressure switch still remains closed, the code is logged and the DO NOT SHIFT response is commanded. If the code is set during a direction change, neutral with no clutches is commanded, otherwise the transmission is commanded to the previous range. Additional codes could be logged for other shifts where ?X? indicates the range from and ?Y? indicates the range to.