Allison
Allison WTEC II Fault Code: 53 PID: SPN: 78 FMI: Offgoing speed test (during shift), R to N1
Posted by PerDiezel Solutions on
Main code 53 indicates a failed offgoing speed test. R?N1 shift The speed test during a shift is designed to ensure neutral is attained during shifts to neutral. This test compares engine speed to turbine speed. If neutral is selected and turbine speed is found to be much lower than engine speed, the ECU sees this as neutral not being attained. The transmission is commanded to Neutral with No Clutches and Code 53 XX is set. Additional codes could be logged for other shifts where ?X? indicates the range from and ?Y? indicates the range to. Allison WTEC II Fault...
Allison WTEC II Fault Code: 53 PID: SPN: 99 FMI: Offgoing speed test (during shift), N2 to N3 or N3 to N2
Posted by PerDiezel Solutions on
Main code 53 indicates a failed offgoing speed test. N3?N2 or N2?N3 shift The speed test during a shift is designed to ensure neutral is attained during shifts to neutral. This test compares engine speed to turbine speed. If neutral is selected and turbine speed is found to be much lower than engine speed, the ECU sees this as neutral not being attained. The transmission is commanded to Neutral with No Clutches and Code 53 XX is set. Additional codes could be logged for other shifts where ?X? indicates the range from and ?Y? indicates the range to. Allison WTEC...
Allison WTEC II Fault Code: 53 PID: SPN: XY FMI: Offgoing speed test, X to Y
Posted by PerDiezel Solutions on
Main code 53 indicates a failed offgoing speed test. X to Y shift The speed test during a shift is designed to ensure neutral is attained during shifts to neutral. This test compares engine speed to turbine speed. If neutral is selected and turbine speed is found to be much lower than engine speed, the ECU sees this as neutral not being attained. The transmission is commanded to Neutral with No Clutches and Code 53 XX is set. Additional codes could be logged for other shifts where ?X? indicates the range from and ?Y? indicates the range to. Allison WTEC...
Allison WTEC II Fault Code: 54 PID: SPN: 01 FMI: Oncoming ratio test (after shift), L to 1
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. L?1 upshift The ratio test after a shift is failed when the ECU has commanded the end of a shift and has not seen the transmission shift into the target range (comparing turbine and output speeds). Erratic readings from speed sensors are a likely cause of an oncoming ratio test failure. If conditions for a shift still exist, the shift will be retried one more time. If the ratio test is still not met, a code is logged and the DO NOT SHIFT response is commanded. If the code is set...
Allison WTEC II Fault Code: 54 PID: SPN: 07 FMI: Oncoming ratio test (after shift), L to R
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. L?R shift The ratio test after a shift is failed when the ECU has commanded the end of a shift and has not seen the transmission shift into the target range (comparing turbine and output speeds). Erratic readings from speed sensors are a likely cause of an oncoming ratio test failure. If conditions for a shift still exist, the shift will be retried one more time. If the ratio test is still not met, a code is logged and the DO NOT SHIFT response is commanded. If the code is set...
