Main code 55 indicates the C3 clutch is the oncoming clutch in a shift and the C3 pressure switch did not close at the end of the shift. Oncoming C3PS (after shift), 2?R shift
When this code is set, the DO NOT SHIFT response and Neutral with No Clutches is commanded. On the N1 to R shift 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.
Main code 55 can also be caused by the EEPROM being calibrated for a close ratio transmission and installed in a wide ratio transmission, or vice versa.
Allison WTEC II Fault Code: 55 PID: SPN: 17 FMI: Oncoming C3PS test (after shift), 1 to R
Allison WTEC II Fault Code: 55 PID: SPN: 07 FMI: Oncoming C3PS test, L to R
Allison WTEC II Fault Code: 54 PID: SPN: XY FMI: Oncoming ratio test, X to Y
Allison WTEC II Fault Code: 54 PID: SPN: 97 FMI: Oncoming ratio test (after shift), 2 to R (2 to NNC to R)
Allison WTEC II Fault Code: 54 PID: SPN: 96 FMI: Oncoming ratio test (after shift), N4 to 6
Allison WTEC II Fault Code: 54 PID: SPN: 95 FMI: Oncoming ratio test (after shift), N3 to 5
