Allison
Allison WTEC II Fault Code: 54 PID: SPN: 24 FMI: Oncoming ratio test (during shift), 2 to 4
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. 2?4 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: 27 FMI: Oncoming ratio test (after shift), 2 to R
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. 2?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...
Allison WTEC II Fault Code: 54 PID: SPN: 32 FMI: Oncoming ratio test (after shift), 3 to 2
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. 3?2 downshift 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: 34 FMI: Oncoming ratio test (after shift), 3 to 4
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. 3?4 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: 35 FMI: Oncoming ratio test (during shift), 3 to 5
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. 3?5 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...
