Main code 24 indicates the ECU has detected either a high or low fluid temperature in the transmission sump (via the sump temperature sensor in the internal harness). No upshifts are allowed above a calibration range when Code 24 23 is set. A related code is 33 12 which indicates a temperature reading outside the usable range of the sensor and indicates a probable sensor failure. Allison WTEC II Fault Code: 24 PID: SPN: 12 FMI: Sump fluid temperature, cold Allison WTEC II Fault Code: 23 PID: SPN: 15 FMI: Secondary Shift Selector Mode Function Fault Allison WTEC II Fault...

Main code 25 occurs if the output speed sensor reports a zero speed reading while both engine and turbine speeds are approximately equal, turbine speed is above a calibration value, and neutral is not selected or commanded. Possible Causes:1. Output speed sensor has failed2. The required oncoming clutch or clutches did not come on. Allison WTEC II Fault Code: 24 PID: SPN: 23 FMI: Sump fluid temperature, hot Allison WTEC II Fault Code: 24 PID: SPN: 12 FMI: Sump fluid temperature, cold Allison WTEC II Fault Code: 23 PID: SPN: 15 FMI: Secondary Shift Selector Mode Function Fault Allison WTEC...

Main code 25 occurs if the output speed sensor reports a zero speed reading while both engine and turbine speeds are approximately equal, turbine speed is above a calibration value, and neutral is not selected or commanded. Possible Causes:1. Output speed sensor has failed2. The required oncoming clutch or clutches did not come on. Code 25 11 can be generated by a false turbine speed reading. This may be due to crosstalk between solenoid and turbine speed sensor circuits caused by direct wire-to-wire short or by water in the electrical connectors. Allison WTEC II Fault Code: 25 PID: SPN: 00...

Main code 25 occurs if the output speed sensor reports a zero speed reading while both engine and turbine speeds are approximately equal, turbine speed is above a calibration value, and neutral is not selected or commanded. Possible Causes:1. Output speed sensor has failed2. The required oncoming clutch or clutches did not come on. Allison WTEC II Fault Code: 25 PID: SPN: 11 FMI: Output speed sensor, detected at 0 output rpm, 1st Allison WTEC II Fault Code: 25 PID: SPN: 00 FMI: Output speed sensor detected at 0 output rpm, Low Allison WTEC II Fault Code: 24 PID: SPN:...

Main code 25 occurs if the output speed sensor reports a zero speed reading while both engine and turbine speeds are approximately equal, turbine speed is above a calibration value, and neutral is not selected or commanded. Possible Causes:1. Output speed sensor has failed2. The required oncoming clutch or clutches did not come on. Allison WTEC II Fault Code: 25 PID: SPN: 22 FMI: Output speed sensor, detected at 0 output rpm, 2nd Allison WTEC II Fault Code: 25 PID: SPN: 11 FMI: Output speed sensor, detected at 0 output rpm, 1st Allison WTEC II Fault Code: 25 PID: SPN:...